ORCID Profile
0000-0002-6745-0570
Current Organisation
Queensland University of Technology
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Macromolecular and Materials Chemistry | Characterisation Of Macromolecules | Physical Chemistry Of Macromolecules | Synthesis of Materials | Synthesis Of Macromolecules | Polymerisation Mechanisms | Chemical Characterisation of Materials | Physical Chemistry of Materials | Nanotechnology | Macromolecular and materials chemistry | Macromolecular Chemistry Not Elsewhere Classified | Nanotechnology | Macromolecular materials | Biomaterials | Macromolecular and Materials Chemistry not elsewhere classified | Physical Organic Chemistry | Organic Chemical Synthesis | Separation Science | Chemistry Of Catalysis | Polymerisation Mechanisms | Nanochemistry and Supramolecular Chemistry | Polymers | Functional Materials | Membrane Biology | Photonics, Optoelectronics and Optical Communications | Nonlinear Optics and Spectroscopy | Polymerisation mechanisms | Organic Chemistry | Biologically Active Molecules | Physical Chemistry (Incl. Structural) | Environmental Technologies | Structural Chemistry and Spectroscopy | Macromolecular and materials chemistry not elsewhere classified | Molecular and Organic Electronics
ANZSRC Socio-Economic Objective (SEO)
Paints | Plastics in primary forms | Polymeric Materials (e.g. Paints) | Synthetic resins and rubber | Polymeric materials (e.g. paints) | Treatments (e.g. chemicals, antibiotics) | Soaps and cosmetics | Rubber and Synthetic Resins | Expanding Knowledge in the Chemical Sciences | Biological sciences | Land and water management | Air quality | Diagnostics | Manufactured products not elsewhere classified | Aerospace Transport not elsewhere classified | Expanding Knowledge in Technology | Industrial chemicals and related products | Energy transformation not elsewhere classified | Industrial Chemicals and Related Products not elsewhere classified | Expanding Knowledge in the Physical Sciences | Scientific Instruments |
Related Links
Publications
λ‐Orthogonale Photochemie: Lichtinduzierte pericyclische Reaktionen an Makromolekülen
Publisher: Wiley
Date: 23-01-2015
Reversible addition–fragmentation chain transfer polymerization initiated with γ-radiation at ambient temperature: an overview
Publisher: Elsevier BV
Date: 03-2003
A Disulfide Intercalator Toolbox for the Site‐Directed Modification of Polypeptides
Publisher: Wiley
Date: 30-10-2014
Abstract: A disulfide intercalator toolbox was developed for site-specific attachment of a broad variety of functional groups to proteins or peptides under mild, physiological conditions. The peptide hormone somatostatin (SST) served as model compound for intercalation into the available disulfide functionalization schemes starting from the intercalator or the reactive SST precursor before or after bioconjugation. A tetrazole-SST derivative was obtained that undergoes photoinduced cycloaddition in mammalian cells, which was monitored by live-cell imaging.
Pd-complex driven formation of single-chain nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5PY00389J
Abstract: The preparation and in-depth characterization of well-defined, palladium( ii ) crosslinked single-chain nanoparticles (Pd-SCNPs) is reported. In addition, a novel procedure for interpreting the SEC chromatograms of SCNPs by log-normal distribution (LND) simulations is introduced.
Light-Controlled Orthogonal Covalent Bond Formation at Two Different Wavelengths.
Publisher: Wiley
Date: 24-04-2019
Abstract: We report light-induced reactions in a two-chromophore system capable of sequence-independent λ-orthogonal reactivity relying solely on the choice of wavelength and solvent. In a solution of water and acetonitrile, LED irradiation at λ
Cycloadditions in Modern Polymer Chemistry
Publisher: American Chemical Society (ACS)
Date: 14-04-2015
DOI: 10.1021/ACS.ACCOUNTS.5B00075
Abstract: Synthetic polymer chemistry has undergone two major developments in the last two decades. About 20 years ago, reversible-deactivation radical polymerization processes started to give access to a wide range of polymeric architectures made from an almost infinite reservoir of functional building blocks. A few years later, the concept of click chemistry revolutionized the way polymer chemists approached synthetic routes. Among the few reactions that could qualify as click, the copper-catalyzed azide-alkyne cycloaddition (CuAAC) initially stood out. Soon, many old and new reactions, including cycloadditions, would further enrich the synthetic macromolecular chemistry toolbox. Whether click or not, cycloadditions are in any case powerful tools for designing polymeric materials in a modular fashion, with a high level of functionality and, sometimes, responsiveness. Here, we wish to describe cycloaddition methodologies that have been reported in the last 10 years in the context of macromolecular engineering, with a focus on those developed in our laboratories. The overarching structure of this Account is based on the three most commonly encountered cycloaddition subclasses in organic and macromolecular chemistry: 1,3-dipolar cycloadditions, (hetero-)Diels-Alder cycloadditions ((H)DAC), and [2+2] cycloadditions. Our goal is to briefly describe the relevant reaction conditions, the advantages and disadvantages, and the realized polymer applications. Furthermore, the orthogonality of most of these reactions is highlighted because it has proven highly beneficial for generating unique, multifunctional polymers in a one-pot reaction. The overview on 1,3-dipolar cycloadditions is mostly centered on the application of CuAAC as the most travelled route, by far. Besides illustrating the capacity of CuAAC to generate complex polymeric architectures, alternative 1,3-dipolar cycloadditions operating without the need for a catalyst are described. In the area of (H)DA cycloadditions, beyond the popular maleimide/furan couple, we present chemistries based on more reactive species, such as cyclopentadienyl or thiocarbonylthio moieties, particularly stressing the reversibility of these systems. In these two greater families, as well as in the last section on [2+2] cycloadditions, we highlight phototriggered chemistries as a powerful tool for spatially and temporally controlled materials synthesis. Clearly, cycloaddition chemistry already has and will continue to transform the field of polymer chemistry in the years to come. Applying this chemistry enables better control over polymer composition, the development of more complicated polymer architectures, the simplification of polymer library production, and the discovery of novel applications for all of these new polymers.
Self-reporting dynamic covalent polycarbonate networks
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6PY01840H
Abstract: The present study introduces the first polycarbonate system that can reversibly be transformed into small molecules.
Multicomponent Reactions in Polymer Chemistry Utilizing Heavier Main Group Elements
Publisher: Wiley
Date: 12-10-2020
Self‐Propagated para ‐Fluoro‐Thiol Reaction
Publisher: Wiley
Date: 08-07-2019
Abstract: We introduce a protecting-group-free concept for the powerful para-fluoro-thiol reaction (PFTR) employing a source of fluoride ions as base. The reaction is shown to be self-propagating, with under-stoichiometric amounts of base, thus effectively foregoing the need for high base concentrations. Careful tuning of the solvent-thiol combination allows for quantitative conversion, in some cases within a short timeframe, when only minimal amounts of base are used, allowing the PFTR reaction to essentially proceed base-free.
Chain Length Dependent Termination in Butyl Acrylate Free-Radical Polymerization Studied via Stationary and Pulsed Laser Initiated RAFT Polymerization
Publisher: American Chemical Society (ACS)
Date: 21-10-2005
DOI: 10.1021/MA051485K
Bioinspired dual self-folding of single polymer chains via reversible hydrogen bonding
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00392E
Emerging investigators 2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9PY90185J
Abstract: This themed issue of Polymer Chemistry highlights the work of emerging investigators in Polymer Chemistry . Editor-in-Chief Christopher Barner-Kowollik introduces the issue.
Near‐Infrared Photoinduced Coupling Reactions Assisted by Upconversion Nanoparticles
Publisher: Wiley
Date: 25-08-2016
Abstract: We introduce nitrile imine-mediated tetrazole-ene cycloadditions (NITEC) in the presence of upconversion nanoparticles (UCNPs) as a powerful covalent coupling tool. When a pyrene aryl tetrazole derivative (λabs, max =346 nm) and UCNPs are irradiated with near-infrared light at 974 nm, rapid conversion of the tetrazole into a reactive nitrile imine occurs. In the presence of an electron-deficient double bond, quantitative conversion into a pyrazoline cycloadduct is observed under ambient conditions. The combination of NITEC and UCNP technology is used for small-molecule cycloadditions, polymer end-group modification, and the formation of block copolymers from functional macromolecular precursors, constituting the first ex le of a NIR-induced cycloaddition. To show the potential for in vivo applications, through-tissue experiments with a biologically relevant biotin species were carried out. Quantitative cycloadditions and retention of the biological activity of the biotin units are possible at 974 nm irradiation.
Reversible single-chain selective point folding via cyclodextrin driven host–guest chemistry in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC03218G
Abstract: In the present communication we introduce a new platform technology for the reversible folding of single polymer chains in aqueous environment on the basis of cyclodextrin (CD) host-guest chemistry and controlled radical polymerization protocols. The single-chain folding of adamantyl-β-CD α-ω-functionalized poly(N,N-dimethylacrylamide) and its reversion at elevated temperatures were monitored by DLS and nuclear Overhauser enhancement spectroscopy (NOESY).
Durch sichtbares Licht induzierte Klick‐Chemie
Publisher: Wiley
Date: 14-07-2015
Supramolecular polymer networks of building blocks prepared via RAFT polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3PY01624B
Oxidative polymerization of catecholamines: structural access by high-resolution mass spectrometry
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY00506G
Abstract: We introduce an avenue for the structural elucidation of bio-inspired functional poly(catecholamines) via high-resolution electrospray ionization mass spectrometry.
Dual-Gated Supramolecular Star Polymers in Aqueous Solution
Publisher: American Chemical Society (ACS)
Date: 14-03-2017
Spatially controlled photochemical peptide and polymer conjugation on biosurfaces
Publisher: American Chemical Society (ACS)
Date: 12-11-2013
DOI: 10.1021/BM401274V
Abstract: An efficient phototriggered Diels-Alder conjugation is utilized to graft in an effective and straightforward approach poly(trifluoro ethyl methacrylate) (Mn = 3700 Da, Đ = 1.27) and a model peptide (GIGKFLHS) onto thin hyaluronan films and cellulose surfaces. The surfaces were functionalized with an o-quinodimethane moiety - capable of releasing a caged diene - via carbodiimide mediated coupling. The o-quinodimethane group is employed as a photoactive linker to tether predefined peptide olymer strands in a spatially controlled manner onto the biosurface by photoenol ligation. An in-depth characterization employing XPS, ToF-SIMS, SPR, ellipsometry, and AFM was conducted to evidence the effectiveness of the presented approach.
Australia and Germany: Large Distance, Close Collaborations
Publisher: Wiley
Date: 13-06-2017
Abstract: "… Both Australia and Germany have long traditions in the chemical sciences, however there is considerable scope to expand collaborations between the two chemical research communities. This can be achieved by collaborative funding opportunities, closing the gap between fundamental research and industrial applications, and targeted interactive symposia …" Read more in the Editorial by Christopher Barner-Kowollik.
SEC Analysis of Poly(Acrylic Acid) and Poly(Methacrylic Acid)
Publisher: Wiley
Date: 27-10-2014
Core‐shell microspheres with surface grafted poly(vinyl alcohol) as drug carriers for the treatment of hepatocellular carcinoma
Publisher: Wiley
Date: 11-06-2007
DOI: 10.1002/POLA.22074
Controlled radical polymerization and in-depth mass-spectrometric characterization of poly(ionic liquid)s and their photopatterning on surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5PY01320H
Abstract: Poly(ionic liquid)s (PILs) bearing a polystyrene backbone prepared via RAFT polymerization and their photolithographic patterning on silicon wafers is reported.
Block copolymers via macromercaptan initiated ring opening polymerization
Publisher: Wiley
Date: 08-12-2010
DOI: 10.1002/POLA.24496
Strengths and limitations of size exclusion chromatography for investigating single chain folding – current status and future perspectives
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9PY00336C
Abstract: Synthetic approaches for Single-Chain Nanoparticles (SCNPs) developed rapidly during the last decade, opening a multitude of avenues for the design of functional macromolecular chains able to collapse into defined nanoparticles. However, the analytical evaluation of the SCNP formation process still requires critical improvements.
Phenanthroline—A Versatile Ligand for Advanced Functional Polymeric Materials
Publisher: Wiley
Date: 12-11-2018
Fabrication of Conductive 3D Gold‐Containing Microstructures via Direct Laser Writing
Publisher: Wiley
Date: 04-2020
Origin of inhibition effects in the reversible addition fragmentation chain transfer (RAFT) polymerization of methyl acrylate
Publisher: American Chemical Society (ACS)
Date: 21-09-2002
DOI: 10.1021/MA0203445
ABC-type miktoarm star terpolymers accessed by H-bonding driven supramolecular self-assembly
Publisher: Elsevier BV
Date: 2015
Designing π-Conjugated Polymeric Nano- and Microstructures via Light Induced Chemistry
Publisher: American Chemical Society (ACS)
Date: 04-12-2015
A New Chemo‐Enzymatic Route to Side‐Chain Liquid‐Crystalline Polymers: The Synthesis and Polymerization of 6‐(4‐Methoxybiphenyl‐4′‐oxy)hexyl Vinyl Hexanedioate
Publisher: Wiley
Date: 11-2003
The Link that Lasts: A New Frontier in Supramolecular Block Copolymer Design
Publisher: Wiley
Date: 03-09-2015
Abstract: Lasting link: A supramolecular linkage between two parts of an hiphilic block copolymer was developed that is sufficiently strong to allow phase-separation-driven nanopatterning as well as chromatographic characterization. The link can also be severed in response to a solvent trigger signal. This powerful approach will open new avenues for the production of self-healing materials, triggered-release systems, and reversible surface designs.
Single chain self-assembly: preparation of α,ω-donor–acceptor chains via living radical polymerization and orthogonal conjugation
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CC00702A
Abstract: Alpha,omega-hydrogen donor/acceptor functional polymer strands are prepared via a combination of living radical polymerization and orthogonal conjugation and subsequently self-assembled as single chains to emulate--on a simple level--the self-folding behaviour of natural biomacromolecules.
Investigation of thermoreversible polymer networks by temperature dependent size exclusion chromatography
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY01262D
Abstract: We introduce a novel approach for studying thermoreversible Diels–Alder networks by Temperature Dependent SEC.
Self-reporting and refoldable profluorescent single-chain nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8SC01009A
Abstract: We pioneer the formation of self-reporting and refoldable profluorescent single-chain nanoparticles (SCNPs) via the light-induced reaction ( λ max = 320 nm) of nitroxide radicals with a photo-active crosslinker.
Reversible Diels-Alder Chemistry as a Modular Polymeric Color Switch
Publisher: Wiley
Date: 06-07-2010
Fluorescent Glyco Single-Chain Nanoparticle-Decorated Nanodiamonds
Publisher: American Chemical Society (ACS)
Date: 04-10-2017
Electrospray Ionization-Mass Spectrometry of Synthetic Polymers Functionalized with Carboxylic Acid End-Groups
Publisher: American Chemical Society (ACS)
Date: 09-07-2021
Platinum(II)‐Crosslinked Single‐Chain Nanoparticles: An Approach towards Recyclable Homogeneous Catalysts
Publisher: Wiley
Date: 03-04-2017
Abstract: We introduce the synthesis and in-depth characterization of platinum(II)-crosslinked single-chain nanoparticles (Pt
Synergistic, Orthogonal, and Antagonistic Photochemistry for Light‐Induced 3D Printing
Publisher: Wiley
Date: 25-10-2022
Abstract: 3D printing techniques are often based on light‐induced chemical reactions, driven by the fascinating and powerful possibilities to control light in space and time. To date, these approaches are usually restricted to a single color of light, which does not do justice to light as an entire spectrum of distinct wavelengths. It is possible to further tap into the vast potential of light‐induced 3D printing by introducing a second color of light. While the complexity of photochemical interactions in two‐color systems is greatly increased, it concomitantly allows for enhanced control over manufacturing speed and resolution. In general, three types of two‐color interactions can be distinguished, i.e., synergistic, orthogonal, and antagonistic. In recent years, intriguing printing techniques with superior potential for the fabrication of 3D structures are emerging that require two colors of light. Their future development potential is vast yet needs to be critically underpinned by an advance in complex tunable photochemical reaction systems. The current perspective will thus explore the potential for using synergistic, orthogonal, and antagonistic photochemistries in 3D printing.
A methoxyamine-protecting group for organic radical battery materials: An alternative approach
Publisher: Wiley
Date: 15-04-2020
Dynamisches makromolekulares Materialdesign – die Vielseitigkeit von Cyclodextrin‐basierter Wirt‐Gast‐Chemie
Publisher: Wiley
Date: 12-06-2017
Multimaterial 3D laser microprinting using an integrated microfluidic system
Publisher: American Association for the Advancement of Science (AAAS)
Date: 02-2019
Abstract: An instrument brings 3D laser printing to a new level, exemplified by 3D fluorescent microstructures composed of five materials.
Reversible Diels–Alder and Michael Addition Reactions Enable the Facile Postsynthetic Modification of Metal–Organic Frameworks
Publisher: American Chemical Society (ACS)
Date: 17-03-2021
Reversible Addition Fragmentation Chain Transfer (RAFT) Polymerization of Methyl Acrylate: Detailed Structural Investigation via Coupled Size Exclusion Chromatography−Electrospray Ionization Mass Spe
Publisher: American Chemical Society (ACS)
Date: 03-01-2004
DOI: 10.1021/MA035244T
Reversible Addition Fragmentation Chain Transfer (
RAFT
) Polymerization: Mechanism, Process and Applications
Publisher: Wiley
Date: 13-01-2012
DOI: 10.1002/9781119953678.RAD058
Abstract: The present article gives an overview of the reversible addition fragmentation chain transfer (RAFT) process. RAFT is one of the most versatile living radical polymerization systems and yields polymers of predictable chain length and narrow molecular weight distribution. RAFT relies on the rapid exchange of thiocarbonyl thio groups between growing polymeric chains. The key strengths of the RAFT process for polymer design are its high tolerance of monomer functionality and reaction conditions, the wide range of well‐controlled polymeric architectures achievable, and its (in‐principle) non‐rate‐retarding nature. This article introduces the mechanism of polymerization, the range of polymer molecular weights achievable, the range of monomers in which polymerization is controlled by RAFT, the various polymeric architectures that can be obtained, the type of end‐group functionalities available to RAFT‐made polymers, and the process of RAFT polymerization.
Einzelkettennanopartikel mit Reaktivität im sichtbaren Lichtspektrum
Publisher: Wiley
Date: 26-04-2023
Abstract: Wir stellen ein Einzelkettennanopartikel (SCNP)‐System vor, welches bei identischer Konzentration die Photooxidation unpolarer Alkene bis zu dreimal effizienter katalysieren kann als ein äquivalenter niedermolekularer Photosensibilisator. Konkret haben wir SCNPs basierend auf Poly(ethylenglykol)methylethermethacrylat und Glycidylmethacrylat entwickelt, welches wir über multifunktionelle Thiol‐Epoxid‐Verknüpfungen in Kombination mit der Funktionalisierung mit Bengalrosa (RB) in einer Eintopfreaktion falten. Die SCNPs weisen sowohl eine hydrophile Hülle als auch hydrophobe photokatalytische Regionen auf. Die Photooxidation des innenliegenden Alkens der Ölsäure verläuft unter Einstrahlung von grünem Licht. Kovalent an die SCNPs gebundenes RB ist dreimal sensitiver gegenüber unpolaren Alkene als freies RB in Lösung. Dies ist unserer Hypothese nach auf die räumliche Nähe der photosensibilisierenden Gruppen zum Substrat in der hydrophoben Region zurückzuführen. Unser Ansatz zeigt, dass SCNP‐basierte Katalysatoren eine verbesserte Photokatalyse durch Einschränkungseffekte (confinement effects) in einer homogenen Reaktionsumgebung ermöglichen können.
Formation efficiency of ABA blockcopolymers via enhanced spin capturing polymerization (ESCP): Locating the alkoxyamine function
Publisher: American Chemical Society (ACS)
Date: 02-07-2009
DOI: 10.1021/MA900356P
Visible Light [2 + 2] Cycloadditions for Reversible Polymer Ligation
Publisher: American Chemical Society (ACS)
Date: 09-05-2018
Mapping the Compaction of Discrete Polymer Chains by Size Exclusion Chromatography Coupled to High-Resolution Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 15-03-2019
Macromolecular Surface Design: Photopatterning of Functional Stable Nitrile Oxides
Publisher: Wiley
Date: 17-03-2015
Abstract: The efficient trapping of photogenerated thioaldehydes with functional shelf-stable nitrile oxides in a 1,3-dipolar cycloaddition is a novel and versatile photochemical strategy for polymer end-group functionalization and surface modification under mild and equimolar conditions. The modular ligation in solution was followed in detail by electrospray ionization mass spectrometry (ESI-MS). X-ray photoelectron spectroscopy (XPS) was employed to analyze the functionalized surfaces, whereas time-of-flight secondary-ion mass spectrometry (ToF-SIMS) confirmed the spatial control of the surface functionalization using a micropatterned shadow mask. Polymer brushes were grown from the surface in a spatially confined regime by surface-initiated atom transfer radical polymerization (SI-ATRP) as confirmed by TOF-SIMS, XPS as well as ellipsometry.
Surface Modification of Poly(divinylbenzene) Microspheres via Thiol−Ene Chemistry and Alkyne−Azide Click Reactions
Publisher: American Chemical Society (ACS)
Date: 27-04-2009
DOI: 10.1021/MA900332D
Front Cover: Phenanthroline—A Versatile Ligand for Advanced Functional Polymeric Materials (Chem. Eur. J. 66/2018)
Publisher: Wiley
Date: 09-11-2018
Chemiluminescent Read-Out of Degradable Fluorescent Polymer Particles
Publisher: American Chemical Society (ACS)
Date: 06-07-2020
Consecutive modular ligation as an access route to palladium containing polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3PY00648D
Evidence for ultrafast formation of tribenzoylgermyl radicals originating from tetraacylgermane photoinitiators
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY00344A
Abstract: We report strong evidence for the ultrafast formation of tribenzoylgermyl radicals originating from tetraacylgermane photoinitiators on a ps-time scale. In comparison to previous studies, the result can be related to a high initiation efficiency.
Single chain self‐assembly of well‐defined heterotelechelic polymers generated by ATRP and click chemistry revisited
Publisher: Wiley
Date: 25-04-2011
DOI: 10.1002/POLA.24688
Wavelength‐Gated Dynamic Covalent Chemistry
Publisher: Wiley
Date: 16-01-2018
Abstract: Chemical reactions are classically controlled by the judicious choice of functional groups as well as external factors such as temperature and catalysts. However, the use of light-induced reactions not only offers precise temporal and spatial control, but critically allows highly specific reaction channels to be selectively addressed through wavelength and intensity, thereby enabling targeted covalent bonds to be made and broken. Photoreversible cycloadditions are the most promising candidates to seize the outlined potential upon selective cyclization and cycloreversion, but are today still far from fulfilling these expectations. The current Minireview critically explores the current challenges in the application of photoreversible cycloadditions and discusses the steps necessary to realize their potential in molecular biology, biomimetic systems, 3D laser lithographic processes, and advanced soft matter materials with reprogrammable and self-healing properties.
π‐Conjugated Polymer–Fullerene Covalent Hybrids via Ambient Conditions Diels–Alder Ligation
Publisher: Wiley
Date: 07-04-2014
Abstract: The established ability of graphitic carbon-nanomaterials to undergo ambient condition Diels-Alder reactions with cyclopentadienyl (Cp) groups is herein employed to prepare fullerene-polythiophene covalent hybrids with improved electron transfer and film forming characteristics. A novel precisely designed polythiophene (M n 9.8 kD, Đ 1.4) with 17 mol% of Cp-groups bearing repeat unit is prepared via Grignard metathesis polymerization. The UV/Vis absorption and fluorescence (λex 450 nm) characteristics of polythiophene with pendant Cp-groups (λmax 447 nm, λe-max 576 nm) are comparable to the reference poly(3-hexylthiophene) (λmax 450 nm, λe-max 576 nm). The novel polythiophene with pendant Cp-groups is capable of producing solvent-stable free-standing polythiophene films, and non-solvent assisted self-assemblies resulting in solvent-stable nanoporous-microstructures. (1) H-NMR spectroscopy reveals an efficient reaction of the pendant Cp-groups with C60 . The UV/Vis spectroscopic analyses of solution and thin films of the covalent and physical hybrids disclose closer donor-acceptor packing in the case of covalent hybrids. AFM images evidence that the covalent hybrids form smooth films with finer lamellar-organization. The effect is particularly remarkable in the case of poorly soluble C60 . A significant enhancement in photo-voltage is observed for all devices constituted of covalent hybrids, highlighting novel avenues to developing efficient electron donor-acceptor combinations for light harvesting systems.
Combining Modular Ligation and Supramolecular Self-Assembly for the Construction of Star-Shaped Macromolecules
Publisher: Wiley
Date: 17-04-2012
A facile one-pot route to poly(carboxybetaine acrylamide) functionalized SWCNTs
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC43361G
Abstract: An unprecedented one-pot procedure employing a cyclopentadienyl functionalized RAFT agent allowed the grafting of poly(carboxybetaine acrylamide) - a highly functional and biocompatible polymer - from the surface of pristine SWCNTs. The pendant carboxylic acid groups of the surface grafted polymer were further conjugated with single-stranded (ss)-DNA, which was successfully hybridized with a Cy5 labelled complementary DNA strand.
Accessing Chain Length Dependent Termination Rate Coefficients of Methyl Methacrylate (MMA) via the Reversible Addition Fragmentation Chain Transfer (RAFT) Process
Publisher: Wiley
Date: 14-10-2005
Direct Synthesis of Well-Defined Heterotelechelic Polymers for Bioconjugations
Publisher: American Chemical Society (ACS)
Date: 19-07-2008
DOI: 10.1021/MA800289U
Prevent or Cure—The Unprecedented Need for Self‐Reporting Materials
Publisher: Wiley
Date: 26-02-2021
Abstract: Self‐reporting smart materials are highly relevant in modern soft matter materials science, as they allow for the autonomous detection of changes in synthetic polymers, materials, and composites. Despite critical advantages of such materials, for ex le, prolonged lifetime or prevention of disastrous material failures, they have gained much less attention than self‐healing materials. However, as diagnosis is critical for any therapy, it is of the utmost importance to report the existence of system changes and their exact location to prevent them from spreading. Thus, we herein critically review the chemistry of self‐reporting soft matter materials systems and highlight how current challenges and limitations may be overcome by successfully transferring self‐reporting research concepts from the laboratory to the real world. Especially in the space of diagnostic self‐reporting systems, the recent SARS‐CoV‐2 (COVID‐19) pandemic indicates an urgent need for such concepts that may be able to detect the presence of viruses or bacteria on and within materials in a self‐reporting fashion.
Entropic Effects on the Supramolecular Self-Assembly of Macromolecules
Publisher: American Chemical Society (ACS)
Date: 07-07-2015
Continuous ATRP Synthesis of Block‐Like Copolymers via Column Reactors: Design and Validation of a Kinetic Model
Publisher: Wiley
Date: 21-11-2009
From Fundamentals to Applications: Living Polymer Science at the 29th Australasian Polymer Symposium
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/CH07332
The bright and the dark side of the sphere: light-stabilized microparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0PY01456G
Abstract: We introduce degradable microparticles, synthesized from prepolymers in a precipitation-like polymerization. The narrow disperse particles are stabilized with continuous irradiation of green light and can be spontaneously degraded in the dark.
Reversible addition fragmentation chain transfer polymerization of sterically hindered monomers: Toward well‐defined rod/coil architectures
Publisher: Wiley
Date: 06-04-2004
DOI: 10.1002/POLA.20098
Wavelength‐Dependent Stiffening of Hydrogel Matrices via Redshifted [2+2] Photocycloadditions
Publisher: Wiley
Date: 20-02-2020
Reversing Adhesion: A Triggered Release Self‐Reporting Adhesive
Publisher: Wiley
Date: 02-02-2016
Exploiting λ-Orthogonal Photoligation for Layered Surface Patterning.
Publisher: Wiley
Date: 20-12-2018
Abstract: We exploit λ-orthogonal photoligation of nitrile imine-mediated tetrazole-ene cycloaddition (NITEC) chemistry to generate complex, interconnected surface modifications via a simple layered surface patterning approach. By judicious choice of activating chromophores, we introduce a one pot reaction where nitrile imine formation can be triggered independently of other tetrazoles present. When irradiated with visible light, a tetrazole bearing a pyrene chromophore undergoes quantitative elimination of nitrogen to release nitrile imine (which subsequently undergoes trapping with a dipolarophile in a 1,3 dipolar cycloaddition) whereas a tetrazole bearing a phenyl moiety remains unreacted. Subsequent irradiation of the solution with UV light yields the N-phenyl containing nitrile imine quantitatively, while the pyrene pyrazoline adduct remains unchanged. This λ-orthogonal photoligation was subsequently exploited for the generation of layered patterned surfaces. Specifically, the visible light active tetrazole was grafted to a silicon wafer and subsequently photolithographically patterned with a dipolarophile modified with a UV-active tetrazole. Various electron deficient olefins were then patterned in a spatially resolved manner relying on different light activation. The desired functionality was successfully imaged on the silicon wafers using time-of-flight-secondary ion mass spectrometry (ToF-SIMS), demonstrating that a powerful mask-less lithographic platform technology has been established.
Chain Length Dependent Termination Rate Coefficients of Methyl Methacrylate (MMA) in the Gel Regime: Accessing kti,i Using Reversible Addition-Fragmentation Chain
Publisher: American Chemical Society (ACS)
Date: 20-03-2007
DOI: 10.1021/MA062405V
Single‐Chain Folding of Synthetic Polymers: A Critical Update
Publisher: Wiley
Date: 23-11-2015
Abstract: The current contribution serves as a critical update to a previous feature article from us (Macromol. Rapid Commun. 2012, 33, 958-971), and highlights the latest advances in the preparation of single chain polymeric nanoparticles and initial-yet promising-attempts towards mimicking the structure of natural biomacromolecules via single-chain folding of well-defined linear polymers via so-called single chain selective point folding and repeat unit folding. The contribution covers selected ex les from the literature published up to ca. September 2015. Our aim is not to provide an exhaustive review but rather highlight a selection of new and exciting ex les for single-chain folding based on advanced macromolecular precision chemistry. Initially, the discussion focuses on the synthesis and characterization of single-chain folded structures via selective point folding. The second part of the feature article addresses the folding of well-defined single-chain polymers by means of repeat unit folding. The current state of the art in the field of single-chain folding indicates that repeat unit folding-driven nanoparticle preparation is well-advanced, while initial encouraging steps towards building selective point folding systems have been taken. In addition, a summary of the-in our view-open key questions is provided that may guide future biomimetic design efforts.
ATRP-based polymers with modular ligation points under thermal and thermomechanical stress
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5PY00036J
Abstract: Functional modular ATRP polymers suffer from accelerated ester cleavage due to HBr release as well as the formation of triazolium salts via the reaction of triazole units with bromine terminal chain ends under thermal and thermomechanical insult.
Delivery of Amonafide from Fructose-Coated Nanodiamonds by Oxime Ligation for the Treatment of Human Breast Cancer.
Publisher: American Chemical Society (ACS)
Date: 23-01-2018
DOI: 10.1021/ACS.BIOMAC.7B01592
Abstract: The introduction of a strategy toward polymer/nanodiamond hybrids with high polymer grafting density and accessible polymer structural characterization is of critical importance for nanodiamonds' surface modification and bioagent attachment for their biomedical application. Here, we report a glycopolymer/nanodiamond hybrid drug delivery system, which was prepared by grafting amonafide-conjugated glycopolymers onto the surface of nanodiamonds via oxime ligation. Poly(1-O-methacryloyl-2,3:4,5-di-O-isopropylidene-β-d-fructopyranose)-b-poly(3-vinylbenzaldehyde-co-methyl methacrylate), featuring pendant aldehyde groups, is prepared via RAFT polymerization. The anticancer drug amonafide is conjugated to the polymer chains via imine chemistry, resulting in acid-degradable imine linkages. The obtained amonafide-conjugated glycopolymers are subsequently grafted onto the surface of aminooxy-functionalized nanodiamonds via oxime ligation. The molecular weight of the conjugated polymers is characterized by size-exclusion chromatography (SEC), while the successful conjugation and corresponding grafting density is assessed by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric aanalysis (TGA). Our results indicate that the mass percentage of amonafide in the polymer chains is around 17% and the surface density of polymer chains is 0.24 molecules/nm
Degradation of Poly(methyl methacrylate) Model Compounds Under Extreme Environmental Conditions
Publisher: Wiley
Date: 17-05-2010
Photocycloadditions in disparate chemical environments
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC03911J
Abstract: We elucidate the wavelength dependence of a photocycloaddition by accessing action plots dependent on the reactivity relative to the number of absorbed photons and establish the effect of concentration and solvent on the reactivity.
No Apparent Correlation of k p with Steric Hindrance for Branched Acrylates
Publisher: Wiley
Date: 12-06-2015
Limitations of cyclodextrin‐mediated RAFT homopolymerization and block copolymer formation
Publisher: Wiley
Date: 13-03-2013
DOI: 10.1002/POLA.26644
Abstract: The design and synthesis of a new hydrophobic monomer, that is, 4‐( tert ‐butyl)phenyl 6‐acrylamidohexanoate (TBP‐AA‐HO) and its ability to form supramolecular host/guest complexes with β‐cyclodextrin (CD) is described. The aqueous CD‐mediated reversible addition fragmentation chain transfer (RAFT) polymerization affords molecular masses up to 8600 g mol −1 with polydispersities between 1.2 and 1.4. The surprisingly low molecular weights for higher monomer/chain transfer agent (CTA) ratios are investigated by comparing results obtained from free radical and RAFT radical polymerization in aqueous and organic media. The results indicate a steric hindrance caused by attached CD molecules on the growing polymer chain leading to stagnation of the polymerization process due to a restricted accessibility of the reactive chain end. This hypothesis is supported by matrix‐assisted laser desorption/ionization time of flight mass spectrometry. Furthermore, the CD‐mediated synthesis of hiphilic diblock copolymers in variable aqueous media is described. Hydrophilic poly( N , N ‐dimethylacrylamide) macro‐CTAs with different molecular weights are used to polymerize TBP‐AA‐HO at 50 °C. The diblock copolymers are analyzed by 1 H‐nuclear magnetic resonance spectroscopy and size exclusion chromatography. The results confirm the polymer structure and reveal similar limitations of chain growth as observed for the CD‐mediated homopolymerization with a limit of 7000 g mol −1 for efficient chain extension. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2504–2517
One-Step Functionalization of Single-Walled Carbon Nanotubes (SWCNTs) with Cyclopentadienyl-Capped Macromolecules via Diels−Alder Chemistry
Publisher: American Chemical Society (ACS)
Date: 07-04-2011
DOI: 10.1021/MA200107Z
Laser Printed Microelectronics
Publisher: Research Square Platform LLC
Date: 28-10-2022
DOI: 10.21203/RS.3.RS-2201014/V1
Abstract: Printed organic and inorganic electronics continue to be of large interest for sensors, bioelectronics, and security applications. Many printing techniques have been investigated, albeit often with typical minimum feature sizes in the tens of micrometer range and requiring post-processing procedures at elevated temperatures to enhance the performance of functional materials. Herein, we introduce laser printing of the semiconductor ZnO and the metals Pt and Ag by laser-induced hydrothermal synthesis and multi-photon reduction, respectively, as a facile process for fabricating printed functional electronic devices with minimum feature sizes below 1 µm. Importantly, no sintering of any sort needs to be performed after laser printing the focused laser light itself induces the necessary local sintering during the printing process. To demonstrate the versatility of our approach, we show functional diodes, memristors, and a physically unclonable function based on a 6×6 memristor crossbar architecture. In addition, we realize functional transistors by combining laser printing and inkjet printing.
Consistent experimental and theoretical evidence for long-lived intermediate radicals in living free radical polymerization
Publisher: American Chemical Society (ACS)
Date: 12-11-2004
DOI: 10.1021/JA046292B
Abstract: The cumyl dithiobenzoate (CDB)-mediated reversible addition fragmentation chain transfer (RAFT) polymerization of styrene at 30 degrees C is studied via both kinetic experiments and high-level ab initio molecular orbital calculations. The kinetic data clearly indicate the delayed onset of steady-state behavior. Such an observation is consistent with the slow fragmentation model for the RAFT process, but cannot be reconciled with the cross-termination model. The comprehensive failure of the cross-termination model is quantitatively demonstrated in a detailed kinetic analysis, in which the independent influences of the pre-equilibria and main equilibria and the possible chain length dependence of cross-termination are fully taken into account. In contrast, the slow fragmentation model can describe the data, provided the main equilibrium has a large fragmentation constant of at least 8.9 x 10(6) L mol(-1). Such a high equilibrium constant (for both equilibria) is consistent with high-level ab initio quantum chemical calculations (K = 7.3 x 10(6) L mol(-1)) and thus appears to be physically realistic. Given that the addition rate coefficient for macroradicals to (polymeric) RAFT agent is 4 x 10(6) L mol(-1) s(-1), this implies that the lifetime of the RAFT adduct radicals is close to 2.5 s. Since the radical is also kinetically stable to termination, it can thus function as a radical sink in its own right.
Titelbild: Dynamisches makromolekulares Materialdesign – die Vielseitigkeit von Cyclodextrin‐basierter Wirt‐Gast‐Chemie (Angew. Chem. 29/2017)
Publisher: Wiley
Date: 20-06-2017
Chemically reprogrammable metal organic frameworks (MOFs) based on Diels–Alder chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC06150A
Abstract: We pioneer a new class of reprogrammable MOFs able to switch their interlattice chemistry via a facile Diels–Alder based cycloreversion process.
Wavelength‐Orthogonal Stiffening of Hydrogel Networks with Visible Light
Publisher: Wiley
Date: 15-02-2022
Abstract: Herein, we introduce the wavelength‐orthogonal crosslinking of hydrogel networks using two red‐shifted chromophores, i.e. acrylpyerene (AP, λ activation =410–490 nm) and styrylpyrido[2,3‐b]pyrazine (SPP, λ activation =400–550 nm), able to undergo [2+2] photocycloaddition in the visible‐light regime. The photoreactivity of the SPP moiety is pH‐dependent, whereby an acidic environment inhibits the cycloaddition. By employing a spiropyran‐based photoacid generator with suitable absorption wavelength, we are able to restrict the activation wavelength of the SPP moiety to the green light region ( λ activation =520–550 nm), enabling wavelength‐orthogonal activation of the AP group. Our wavelength‐orthogonal photochemical system was successfully applied in the design of hydrogels whose stiffness can be tuned independently by either green or blue light.
Highly Selective Dispersion of Single-Walled Carbon Nanotubes via Polymer Wrapping: A Combinatorial Study via Modular Conjugation
Publisher: American Chemical Society (ACS)
Date: 11-12-2013
DOI: 10.1021/MZ400472Q
Click reactive microgels as a strategy towards chemically injectable hydrogels
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6PY01663D
Abstract: Doubly crosslinked microgels (DX microgels) are hydrogels constructed by covalently interlinked microgel particles, offering two levels of hierarchy within the network, the first one being the microgel and the second being the interlinked microgel network.
Mixed, Multicompartment, or Janus Micelles? A Systematic Study of Thermoresponsive Bis-Hydrophilic Block Terpolymers
Publisher: American Chemical Society (ACS)
Date: 13-05-2010
DOI: 10.1021/LA101173B
Abstract: We present a systematic investigation of the extent of compartmentalization in micelles formed by a series of bis-hydrophilic block terpolymers with two outer water-soluble segments. The corona blocks are constructed from poly(ethylene oxide) (PEO) and the thermoresponsive poly(N-isopropyl-acrylamide) (PNiPAAm). The fraction of PNiPAAm is varied to establish its influence on the supramicellar aggregation and corona phase behavior. We demonstrate that--when the collapse of PNiPAAm is triggered--a clustering of micelles into superstructures only occurs when the contour length of the thermoresponsive block is longer than that of the PEO chains. The volume fractions play a minor role. The extent of superstructure formation increases with the amount of heating cycles, pointing to a rearrangement of micelles with a mixed corona into a phase-segregated corona. The collapse of PNiPAAm is exploited to artificially raise the incompatibility and drive phase segregation. A uniform population of biphasic Janus micelles cannot be obtained. After repeated heating cycles, the mixture consists of a range of multicompartment architectures, whose patch distribution can be derived from aggregate structures found in cryo-TEM obtained at high temperature. In the last section, we relate our results to previously studied systems and attempt to derive some generalities. First, we try to answer the question of how likely it is in terms of thermodynamics to obtain truly self-assembled Janus micelles. Furthermore, our results can provide an estimation for the volume ratio or/and block lengths required in micelles composed out of two corona blocks to induce supramicellar aggregation when a hydrophilic-to-hydrophobic phase transition is triggered in one of the blocks.
Surface Grafting via Photo‐Induced Copper‐Mediated Radical Polymerization at Extremely Low Catalyst Concentrations
Publisher: Wiley
Date: 06-07-2015
Abstract: Surface-initiated photo-induced copper-mediated radical polymerization is employed to graft a wide range of polyacrylate brushes from silicon substrates at extremely low catalyst concentrations. This is the first time that the controlled nature of the reported process is demonstrated via block copolymer formation and re-initiation experiments. In addition to unmatched copper catalyst concentrations in the range of few ppb, film thicknesses up to almost 1 μm are achieved within only 1 h.
Single Chain Folding of Synthetic Polymers by Covalent and Non‐Covalent Interactions: Current Status and Future Perspectives
Publisher: Wiley
Date: 05-04-2012
Abstract: The present feature article highlights the preparation of polymeric nanoparticles and initial attempts towards mimicking the structure of natural biomacromolecules by single chain folding of well-defined linear polymers through covalent and non-covalent interactions. Initially, the discussion focuses on the synthesis and characterization of single chain self-folded structures by non-covalent interactions. The second part of the article summarizes the folding of single chain polymers by means of covalent interactions into nanoparticle systems. The current state of the art in the field of single chain folding indicates that covalent-bond-driven nanoparticle preparation is well advanced, while the first encouraging steps towards building reversible single chain folding systems by the use of mutually orthogonal hydrogen-bonding motifs have been made.
Nitrone‐Mediated Radical Coupling of Polymers Derived from Reverse Iodine‐Transfer Polymerization
Publisher: Wiley
Date: 20-02-2014
Highly Orthogonal Functionalization of ADMET Polymers via Photo-Induced Diels–Alder Reactions
Publisher: American Chemical Society (ACS)
Date: 07-06-2012
DOI: 10.1021/MA3007043
Single-Chain Folding of Diblock Copolymers Driven by Orthogonal H-Donor and Acceptor Units
Publisher: American Chemical Society (ACS)
Date: 19-08-2014
DOI: 10.1021/MA501186K
Enhanced Spin Capturing Polymerization of Ethylene
Publisher: American Chemical Society (ACS)
Date: 05-10-2012
DOI: 10.1021/MA3014806
Visible‐Light‐Induced Passerini Multicomponent Polymerization
Publisher: Wiley
Date: 19-03-2019
Pyreneacyl sulfides as a visible light-induced versatile ligation platform
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC00711F
Abstract: We report a visible light responsive moiety capable of generating highly reactive thioaldehydes.
Simultaneous Dual Encoding of Three‐Dimensional Structures by Light‐Induced Modular Ligation
Publisher: Wiley
Date: 17-02-2016
Abstract: A highly efficient strategy for the simultaneous dual surface encoding of 2D and 3D microscaffolds is reported. The combination of an oligo(ethylene glycol)-based network with two novel and readily synthesized monomers with photoreactive side chains yields two new photoresists, which can be used for the fabrication of microstructures (by two-photon polymerization) that exhibit a dual-photoreactive surface. By combining both functional photoresists into one scaffold, a dual functionalization pattern can be obtained by a single irradiation step in the presence of adequate reaction partners based on a self-sorting mechanism. The versatility of the approach is shown by the dual patterning of halogenated and fluorescent markers as well as proteins. Furthermore, we introduce a new ToF-SIMS mode ("delayed extraction") for the characterization of the obtained microstructures that combines high mass resolution with improved lateral resolution.
Elucidation of Reaction Mechanisms and Polymer Structure: Living/Controlled Radical Polymerization
Publisher: Wiley
Date: 07-12-2011
Photochemically Induced Folding of Single Chain Polymer Nanoparticles in Water
Publisher: American Chemical Society (ACS)
Date: 29-12-2016
Molecular Photoswitching of Main-Chain α-Bisimines in Solid-State Polymers
Publisher: American Chemical Society (ACS)
Date: 28-06-2023
DOI: 10.1021/JACS.3C03242
Controlled growth of protein resistant PHEMA brushes via S-RAFT polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TB20880J
Scope for Accessing the Chain Length Dependence of the Termination Rate Coefficient for Disparate Length Radicals in Acrylate Free Radical Polymerization
Publisher: Wiley
Date: 02-2007
Current Trends in the Field of Self‐Healing Materials
Publisher: Wiley
Date: 12-12-2011
Photophysical Properties of Benzoylgermane and para‐Substituted Derivatives: Substituent Effects on Electronic Transitions
Publisher: Wiley
Date: 16-09-2016
Abstract: In the present study, a selection of basic substitution patterns on benzoyl(trimethyl)germane was investigated using time-dependent density-functional theory (TDDFT) to explore the influence on the stability and on the relative order of the lowest excited electronic states. The theoretical results are in agreement with absorption and fluorescence measurements. We show that electron-withdrawing groups decrease the energetic level of the lowest singlet and triplet state relative to the electron-pushing systems resulting in red-shifted radiative transitions (fluorescence). In the first triplet state electron-withdrawing groups lead to an increased dissociation barrier and a close approach with the singlet ground state before the transition state in the triplet state is reached, favoring radiationless ground-state recovery. The results are also in good agreement with empirical concepts of organic chemistry, therefore providing simple rules for synthetic strategies towards tuning the excited-state properties of benzoylgermanes.
Phototriggered Functionalization of Hierarchically Structured Polymer Brushes
Publisher: American Chemical Society (ACS)
Date: 20-05-2015
DOI: 10.1021/ACS.LANGMUIR.5B01114
Abstract: The precise design of bioactive surfaces, essential for the advancement of many biomedical applications, depends on achieving control of the surface architecture as well as on the ability to attach bioreceptors to antifouling surfaces. Herein, we report a facile avenue toward hierarchically structured antifouling polymer brushes of oligo(ethylene glycol) methacrylates via surface-initiated atom transfer radical polymerization (SI-ATRP) presenting photoactive tetrazole moieties, which permitted their functionalization via nitrile imine-mediated tetrazole-ene cyclocloaddition (NITEC). A maleimide-functional ATRP initiator was photoclicked to the side chains of a brush enabling a subsequent polymerization of carboxybetaine acrylamide to generate a micropatterned graft-on-graft polymer architecture as evidenced by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Furthermore, the spatially resolved biofunctionalization of the tetrazole-presenting brushes was accessed by the photoligation of biotin-maleimide and subsequent binding of streptavidin. The functionalized brushes bearing streptavidin were able to resist the fouling from blood plasma (90% reduction with respect to bare gold). Moreover, they were employed to demonstrate a model biosensor by immobilization of a biotinylated antibody and subsequent capture of an antigen as monitored in real time by surface plasmon resonance.
Two Photon Induced Pulsed Laser Polymerization with Near Infrared Light
Publisher: American Chemical Society (ACS)
Date: 14-02-2023
Photostationary State in Dynamic Covalent Networks
Publisher: American Chemical Society (ACS)
Date: 31-03-2022
DOI: 10.1021/ACSMACROLETT.2C00097
Abstract: We explore a cross-linked polymer network based on a visible light photodynamic [2 + 2] cycloaddition driven by styrylpyrene chemistry. Based on a polymer backbone with pendent styrylpyrene units, the network can be formed by using λ = 450 nm irradiation. Upon irradiation with λ = 340 nm, a photostationary state is generated within the network with ∼17% of the styrylpyrene units open compared to close to 2% in the visible light cured state. The limited fraction of open [2 + 2] couples is caused by their proximity and is in sharp contrast to solution experiments on the photoreactive moiety. Thus, the polymer network retains its mechanical properties even at the photostationary point. We hypothesize that the application of an additional stimulus could serve as a second gate for inducing network disintegration by spacing the [2 + 2] units during ultraviolet irradiation.
Modular Ligation of Thioamide Functional Peptides onto Solid Cellulose Substrates
Publisher: Wiley
Date: 04-06-2012
An alternative method to estimate the bulk backbiting rate coefficient in acrylate radical polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6PY01468B
Abstract: An alternative method to estimate the backbiting rate coefficient in acrylate polymerization is presented and successfully applied to experimental data.
Chiral Mono(borohydride) Complexes of Scandium and Lutetium and Their Catalytic Activity in Ring-Opening Polymerization of dl -Lactide
Publisher: American Chemical Society (ACS)
Date: 22-05-2018
Well-Defined Protein−Polymer Conjugates via in Situ RAFT Polymerization
Publisher: American Chemical Society (ACS)
Date: 15-05-2007
DOI: 10.1021/JA070956A
Abstract: Biotechnology, biomedicine, and nanotechnology applications would benefit from methods generating well-defined, monodisperse protein-polymer conjugates, avoiding time-consuming and difficult purification steps. Herein, we report the in situ synthesis of protein-polymer conjugates via reversible addition-fragmentation chain transfer polymerization (RAFT) as an efficient method to generate well-defined, homogeneous protein-polymer conjugates in one step, eliminating major postpolymerization purification steps. A water soluble RAFT agent was conjugated to a model protein, bovine serum albumin (BSA), via its free thiol group at Cys-34 residue. The conjugation of the RAFT agent to BSA was confirmed by UV-visible spectroscopy, matrix-assisted laser desorption ionization--time of flight (MALDI-TOF), and 1H NMR. BSA-macroRAFT agent was then used to control the polymerization of two different water soluble monomers, N-isopropylacrylamide (NIPAAm) and hydroxyethyl acrylate (HEA), in aqueous medium at 25 degrees C. The growth of the polymer chains from BSA-macroRAFT agent was characterized by size exclusion chromatography (SEC), 1H NMR, MALDI-TOF, and polyacrylamide gel electrophoresis (PAGE) analyses. The controlled character of the RAFT polymerizations was confirmed by the linear evolution of molecular weight with monomer conversion. The SEC analyses showed no detectable free, nonconjugated polymer formation during the in situ polymerization. The efficiency of BSA-macroRAFT agent to generate BSA-polymer conjugates was found to be ca. 1 by deconvolution of the SEC traces of the polymerization mixtures. The structural integrity and the conformation-related esterase activity of BSA were found to be unaffected by the polymerization conditions and the conjugation of the polymer chain. BSA-poly(NIPAAm) conjugates showed hybrid temperature-dependent phase separation and aggregation behavior. The lower critical solution temperature values of the conjugates were found to increase with the decrease in molecular weight of poly(NIPAAm) block conjugated to BSA.
Two‐in‐One: λ‐Orthogonal Photochemistry on a Radical Photoinitiating System
Publisher: Wiley
Date: 29-11-2016
Abstract: An alkyne functional radical photoinitiator, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl hex-5-ynoate, and evidence that both reactive moieties - the alkyne and the photoinitiator terminus - can be independently addressed with light of disparate wavelength (λ-orthogonality) are introduced. The alkyne functionality is subjected to a visible light (420 nm) induced copper-catalyzed Huisgen reaction, which is employed for the selective functionalization of the initiator with a poly(ethylene glycol) (PEG) chain. This reaction proceeds completely λ-orthogonal in the presence of the UV-reactive photoinitiating moiety. Conversely, it is demonstrated that the alkyne functionality of the photoinitiator is quantitatively orthogonal to UV irradiation emitted by the pulsing action of an excimer laser (351 nm, pulsed-laser polymerization, PLP) and the generated radical species. In turn, the PEGylated initiator can readily be employed as a macrophotoinitiator during PLP. The introduced λ-orthogonally addressable dual functional initiator can be used in a wide range of applications, including surface lithography and post-synthetic modification of photocured materials.
Modular ambient temperature functionalization of carbon nanotubes with stimuli-responsive polymer strands
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2PY20928D
RAFT-Mediated ab Initio Emulsion Copolymerization of 1,3-Butadiene with Acrylonitrile
Publisher: American Chemical Society (ACS)
Date: 23-04-2014
DOI: 10.1021/MA500055Q
Dependence of termination kinetics in methyl acrylate-dodecyl acrylate free-radical copolymerization on comonomer composition, pressure, temperature and conversion
Publisher: Wiley
Date: 09-2002
DOI: 10.1002/1521-3935(200209)203:13<1887::AID-MACP1887>3.0.CO;2-2
From n-butyl acrylate Arrhenius parameters for backbiting and tertiary propagation to β-scission via stepwise pulsed laser polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9PY00623K
Abstract: A stepwise method to estimate the Arrhenius parameters for backbiting, tertiary propagation, and β-scission in acrylate radical polymerization.
Quantitative Product Spectrum Analysis of Poly(butyl acrylate) via Electrospray Ionization Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 25-11-2008
DOI: 10.1021/MA801196W
Comb Polymers with Triazole Linkages under Thermal and Mechanical Stress
Publisher: American Chemical Society (ACS)
Date: 03-01-2019
Exploring the Mechanisms in STED‐Enhanced Direct Laser Writing
Publisher: Wiley
Date: 25-11-2014
Cumyl phenyldithioacetate and 1-phenylethyl phenyldithioacetate: Versatile ambient-temperature RAFT agents
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/CH01149
Quantum chemical mapping of initialization processes in RAFT polymerization
Publisher: Wiley
Date: 03-07-2006
Determining free-radical propagation rate coefficients with high-frequency lasers: Current status and future perspectives
Publisher: Wiley
Date: 19-10-2016
Abstract: Detailed knowledge of the polymerization mechanisms and kinetics of academically and industrially relevant monomers is mandatory for the precision synthesis of tailor‐made polymers. The IUPAC‐recommended pulsed‐laser polymerization–size exclusion chromatography (PLP–SEC) approach is the method of choice for the determination of propagation rate coefficients and the associated Arrhenius parameters for free radical polymerization processes. With regard to specific monomer classes—such as acrylate‐type monomers, which are very important from a materials point of view—high laser frequencies of up to 500 Hz are mandatory to prevent the formation of mid‐chain radicals and the occurrence of chain‐breaking events by chain transfer, if industrially relevant temperatures are to be reached and wide temperature ranges are to be explored (up to 70 °C). Herein the progress and state‐of‐the‐art of high‐frequency PLP–SEC with pulse repetition rates of 500 Hz is reported, with a critical collection of to‐date investigated 500 Hz data as well as future perspectives for the field. image
Photochemical Design of Stimuli-Responsive Nanoparticles Prepared by Supramolecular Host–Guest Chemistry
Publisher: American Chemical Society (ACS)
Date: 24-06-2015
Visible Light Switchable Single-Chain Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 10-10-2022
Direct light-induced (co-)grafting of photoactive polymers to graphitic nanodiamonds
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6PY02035F
Abstract: We report the light-driven grafting and controlled simultaneous co-grafting of various functional polymers to graphitic nanodiamonds (grNDs).
Photo-Sensitive RAFT-Agents for Advanced Microparticle Design
Publisher: American Chemical Society (ACS)
Date: 20-08-2013
DOI: 10.1021/MA401242G
Well-Defined Diblock Glycopolymers from RAFT Polymerization in Homogeneous Aqueous Medium
Publisher: American Chemical Society (ACS)
Date: 08-10-2005
DOI: 10.1021/MA051310A
RAFT and click chemistry: A versatile approach to well-defined block copolymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B611224B
Abstract: The combination of reversible chain transfer chemistry with highly orthogonal [2 + 3] cycloadditions ('click chemistry') allows for the synthesis of well-defined block copolymers of monomers with extremely disparate reactivities.
Photoinduced Conjugation of Dithioester- and Trithiocarbonate-Functional RAFT Polymers with Alkenes
Publisher: American Chemical Society (ACS)
Date: 08-11-2011
DOI: 10.1021/MA101893U
Advanced Computational Strategies for Modelling the Evolution of Full Molecular Weight Distributions Formed During Multiarmed (Star) Polymerisations
Publisher: Wiley
Date: 30-03-2005
Light‐Induced Modular Ligation of Conventional RAFT Polymers
Publisher: Wiley
Date: 22-10-2012
Abstract: Making light work of RAFT conjugation: a non-activated RAFT agent at the end of RAFT polymers can readily be coupled with ortho-quinodimethanes (photoenols) in a photo-triggered Diels-Alder reaction under mild conditions without catalyst. The method is universal and opens the door for the conjugation of a large number of RAFT-prepared polymers with photoenol-functionalized (macro)molecules. (RAFT=reversible addition-fragmentation chain transfer.).
Dual thermo- and photo-responsive micelles based on miktoarm star polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3PY00576C
A complete kinetic study of a versatile functional monomer: acetoacetoxyethyl methacrylate (AAEMA)
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6PY01115B
Abstract: The current study reports the complete kinetic analysis of acetoacetoxyethyl methacrylate (AAEMA).
Inkjet‐Printed Self‐Hosted TADF Polymer Light‐Emitting Diodes
Publisher: Wiley
Date: 19-07-2022
Abstract: Thermally activated delayed fluorescent (TADF) materials are extensively investigated as organic light‐emitting diodes (OLEDs) with TADF emitting layers demonstrating high efficiency without the use of heavy metal complexes. Therefore, solution‐processable and printable TADF emitters are highly desirable, moving away from expensive vacuum deposition techniques. In addition, using emissive materials not requiring an external host simplifies the fabrication process significantly. Herein, OLEDs using a solution‐processable TADF polymer that do not need an external host are introduced. The non‐conjugated TADF polymer features a TADF emitter (4‐(9H‐carbazol‐9‐yl)‐2‐(3′‐hydroxy‐[1,1′‐biphenyl]‐3‐yl)‐isoindoline‐1,3‐dione) as a side chain, as well as a hole‐transporting side chain and an electron‐transporting side chain on an inactive polymer backbone. All organic layers of the OLEDs are fabricated using solution processing methods. The OLEDs with inkjet‐printed emissive layers have comparable maximum current and external quantum efficiency as their spin‐coated counterparts, exceeding luminance of 2000 cd m −2 . The herein‐explored strategy is a viable route toward self‐hosted printable TADF OLEDs.
STED-Inspired Laser Lithography Based on Photoswitchable Spirothiopyran Moieties
Publisher: American Chemical Society (ACS)
Date: 15-01-2019
Single‐pulse pulsed laser polymerization–electron paramagnetic resonance investigations into the termination kinetics of n‐butyl acrylate macromonomers
Publisher: Wiley
Date: 17-08-2012
DOI: 10.1002/POLA.26295
Abstract: The termination of model mid‐chain radicals (MCRs), which mimic radicals that occur in acrylate polymerization over a broad range of reaction conditions, has been studied by single‐pulse pulsed laser polymerization (SP‐PLP) in conjunction with electron paramagnetic resonance spectroscopy. The model radicals were generated by initiator‐fragment addition to acrylic macromonomers that were preformed prior to the kinetic experiments, thus enabling separation of termination from the propagation reaction, for these model radicals propagate sparingly, if at all, on the timescale of SP‐PLP experiments. Termination rate coefficients of the MCRs were determined in the temperature range of 0–60°C in acetonitrile and butyl propionate solution as well as in bulk macromonomer over the range of 0–100 °C. Termination rate coefficients slightly below those of the corresponding secondary radicals were deduced, demonstrating the relatively high termination activity of this species, even when undergoing MCR–MCR termination. For chain length of 10, a reduction by a factor of 6 is observed. Unusually high activation energies were found for the termination rate coefficient in these systems, with 35 kJ mol −1 being determined for bulk macromonomer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Multi-Block Polyurethanes via RAFT End-Group Switching and Their Characterization by Advanced Hyphenated Techniques
Publisher: American Chemical Society (ACS)
Date: 06-08-2012
DOI: 10.1021/MA301117K
Accessing the Chain Length Dependence of the Termination Rate Coefficient for Disparate Length Radicals via Reversible Addition Fragmentation Chain Transfer Chemistry: A Theoretical Study
Publisher: American Chemical Society (ACS)
Date: 27-06-2006
DOI: 10.1021/MA060646X
Thermally reversible Diels-Alder-based polymerization: an experimental and theoretical assessment
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00356A
Photochemically Activated 3D Printing Inks: Current Status, Challenges, and Opportunities
Publisher: Wiley
Date: 08-09-2023
Synthesis of Single‐Ring Nanoparticles Mimicking Natural Cyclotides by a Stepwise Folding‐Activation‐Collapse Process
Publisher: Wiley
Date: 24-08-2018
Abstract: Cyclotides are small cyclic polypeptides found in a variety of organisms, ranging from bacteria to plants. Their ring structure endows those polypeptides with specific properties, such as improved stability against enzymatic degradation. Optimal cyclotide activity is often observed only in the presence of intra-ring disulfide bonds. Synthesis of soft nano-objects mimicking the conformation of natural cyclotides remains challenging. Here, a new class of natural cyclotide mimics synthesized by a stepwise folding-activation-collapse process at high dilution starting from simple synthetic precursor polymers is established. The initial folding step is carried out by a photoactivated hetero Diels-Alder (HDA) ring-closing reaction, which is accompanied by chain compaction of the in idual precursor polymer chains as determined by size exclusion chromatography (SEC). The subsequent activation step comprises a simple azidation procedure, whereas the final collapse step is driven by CuAAC in the presence of an external cross-linker, providing additional compaction to the final single-ring nanoparticles (SRNPs). The unique structure and compaction degree of the SRNPs is established via a detailed comparison with conventional single-chain nanoparticles (SCNPs) prepared exclusively by chain collapse from the exact same precursor polymer (without the prefolding step). The stepwise folding-activation-collapse approach opens new avenues for the preparation of artificial cyclotide mimetics.
Laser Photodissociation Action Spectroscopy for the Wavelength-Dependent Evaluation of Photoligation Reactions
Publisher: American Chemical Society (ACS)
Date: 21-05-2021
Revealing the Wavelength Dependence of Photochemical Reactions: Cutting-Edge Research in the Teaching Lab
Publisher: American Chemical Society (ACS)
Date: 18-11-2019
Transesterification of poly(ethyl‐α‐hydroxymethacrylate) prepared via reversible addition–fragmentation chain transfer polymerization
Publisher: Wiley
Date: 04-10-2005
DOI: 10.1002/POLA.20991
An in-depth analytical approach to the mechanism of the RAFT process in acrylate free radical polymerizations via coupled size exclusion chromatography–electrospray ionization mass spectrometry (SEC–E
Publisher: Elsevier BV
Date: 09-2005
RAFT Polymerization of N‐Isopropylacrylamide and Acrylic Acid under γ‐Irradiation in Aqueous Media
Publisher: Wiley
Date: 22-05-2006
Shining Light on Poly(ethylene glycol): From Polymer Modification to 3D Laser Printing of Water Erasable Microstructures
Publisher: Wiley
Date: 09-07-2020
Revealing model dependencies in 'Assessing the RAFT equilibrium constant via model systems: An EPR study'
Publisher: Wiley
Date: 20-10-2011
Abstract: In a recent article (W. Meiser, M. Buback, Assessing the RAFT Equilibrium Constant via Model Systems: An EPR Study, Macromol. Rapid Commun. 2011, 18, 1490-1494), it is claimed that evidence is found that unequivocally proves that quantum mechanical calculations assessing the equilibrium constant and fragmentation rate coefficients in dithiobenzoate-mediated reversible addition fragmentation transfer (RAFT) systems are beset with a considerable uncertainty. In the present work, we show that these claims made by Meiser and Buback are beset with a model dependency, as a critical key parameter in their data analysis - the addition rate coefficient of the radicals attacking the C=S double bond in the dithiobenzoate - induces a model insensitivity into the data analysis. Contrary to the claims made by Meiser and Buback, their experimental results can be brought into agreement with the quantum chemical calculations if a lower addition rate coefficient of cyanoisopropyl radicals (CIP) to the CIP dithiobenzoate (CPDB) is assumed. To resolve the model dependency, the addition rate coefficient of CIP radicals to CPDB needs to be determined as a matter of priority.
Fabrication and Spatially Resolved Functionalization of 3D Microstructures via Multiphoton‐Induced Diels–Alder Chemistry
Publisher: Wiley
Date: 10-03-2014
3D Laser Micro‐ and Nanoprinting: Challenges for Chemistry
Publisher: Wiley
Date: 15-11-2017
Abstract: 3D printing is a powerful emerging technology for the tailored fabrication of advanced functional materials. This Review summarizes the state-of-the art with regard to 3D laser micro- and nanoprinting and explores the chemical challenges limiting its full exploitation: from the development of advanced functional materials for applications in cell biology and electronics to the chemical barriers that need to be overcome to enable fast writing velocities with resolution below the diffraction limit. We further explore chemical means to enable direct laser writing of multiple materials in one resist by highly wavelength selective (λ-orthogonal) photochemical processes. Finally, chemical processes to construct adaptive 3D written structures that are able to respond to external stimuli, such as light, heat, pH value, or specific molecules, are highlighted, and advanced concepts for degradable scaffolds are explored.
Temperature-dependent size exclusion chromatography for the in situ investigation of dynamic bonding/debonding reactions
Publisher: Springer Science and Business Media LLC
Date: 23-07-2013
DOI: 10.1007/S00216-013-7203-8
Abstract: Polymers capable of dynamic bonding/debonding reactions are of great interest in modern day research. Potential applications can be found in the fields of self-healing materials or printable networks. Since temperature is often used as a stimulus for triggering reversible bonding reactions, an analysis operating at elevated temperatures is very useful for the in situ investigation of the reaction mechanism, as unwanted side effects can be minimized when performing the analyses at the same temperature at which the reactions occur. A temperature-dependent size exclusion chromatographic system (TD SEC) has been optimized for investigating the kinetics of retro Diels-Alder-based depolymerization of Diels-Alder polymers. The changing molecular weight distribution of the analyzed polymers during depolymerization gives valuable quantitative information on the kinetics of the reactions. Adequate data interpretation methods were developed for the correct evaluation of the chromatograms. The results are confirmed by high-temperature dynamic light scattering, thermogravimetric analysis, and time-resolved nuclear magnetic resonance spectroscopy at high temperatures. In addition, the SEC system and column material stability under application conditions were assessed using thermoanalysis methods, infrared spectroscopy, nitrogen physisorption, and scanning electron microscopy. The findings demonstrate that the system is stable and, thus, we can reliably characterize such dynamically bonding/debonding systems with TD SEC.
Depropagation kinetics of sterically demanding monomers: A pulsed laser size exclusion chromatography study
Publisher: American Chemical Society (ACS)
Date: 15-06-2005
DOI: 10.1021/MA050444L
Selective functionalization of laser printout patterns on cellulose paper sheets coated with surface-specific peptides
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TA02524F
Abstract: Laser printed patterns on paper are coated with surface-specific peptides and modified via photo-induced ligation to yield functional surfaces.
Neoglycopolymers Based on 4-Vinyl-1,2,3-Triazole Monomers Prepared by Click Chemistry
Publisher: Wiley
Date: 08-02-2010
Abstract: The synthesis of a new glycomonomer based on mannose, prepared via CuAAC, is reported. The resulting 1,2,3-triazole linkage between mannose and the polymer backbone ensures the formation of highly stable glycopolymers, which will not undergo hydrolysis. The monomer 2'-(4-vinyl-[1,2,3]-triazol-1-yl)ethyl-O-alpha-D-mannopyranoside was polymerized in the presence of a RAFT agent - 3-benzylsulfanylthiocarbonylsulfanyl propionic acid - to yield well-defined polymers with molecular weights up to 51,500 g mol(-1) and a PDI of 1.16. The resulting polymer was employed as a macroRAFT agent in the polymerization of NIPAAm in order to generate thermo-responsive block copolymers, which undergo reversible micelle formation at elevated temperatures. The rapid interaction between the polymers prepared and ConA confirms the high affinity of these structures to proteins. While the linear glycopolymers already undergo a fast complexation with ConA, the reported rates have found to be exceeded by the micellar glycopolymer structure presented in the current contribution.
Mild and Modular Surface Modification of Cellulose via Hetero Diels−Alder (HDA) Cycloaddition
Publisher: American Chemical Society (ACS)
Date: 02-03-2011
DOI: 10.1021/BM101461H
Abstract: A combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and hetero Diels-Alder (HDA) cycloaddition was used to effect, under mild (T ≈ 20 °C), fast, and modular conditions, the grafting of poly(isobornyl acrylate) (M(n) = 9800 g mol(-1), PDI = 1.19) onto a solid cellulose substrate. The active hydroxyl groups expressed on the cellulose fibers were converted to tosylate leaving groups, which were subsequently substituted by a highly reactive cyclopentadienyl functionality (Cp). By employing the reactive Cp-functionality as a diene, thiocarbonyl thio-capped poly(isobornyl acrylate) synthesized via RAFT polymerization (mediated by benzyl pyridine-2-yldithioformiate (BPDF)) was attached to the surface under ambient conditions by an HDA cycloaddition (reaction time: 15 h). The surface-modified cellulose s les were analyzed in-depth by X-ray photoelectron spectroscopy, scanning electron microscopy, elemental analysis, Fourier transform infrared (FT-IR) spectroscopy as well as Fourier transform infrared microscopy employing a focal plane array detector for imaging purposes. The analytical results provide strong evidence that the reaction of suitable dienophiles with Cp-functional cellulose proceeds under mild reaction conditions (T ≈ 20 °C) in an efficient fashion. In particular, the visualization of in idual modified cellulose fibers via high-resolution FT-IR microscopy corroborates the homogeneous distribution of the polymer film on the cellulose fibers.
Ambient temperature polymer modification by in situ phototriggered deprotection and thiol–ene chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00372K
Recodable surfaces based on switchable hydrogen bonds
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC03612K
Abstract: We introduce recodable surfaces solely based on reversible artificial hydrogen bonding interactions.
Visual recognition of supramolecular graft polymer formation via phenolphthalein–cyclodextrin association
Publisher: Elsevier BV
Date: 08-2013
Elucidating the Early Steps in Photoinitiated Radical Polymerization via Femtosecond Pump–Probe Experiments and DFT Calculations
Publisher: American Chemical Society (ACS)
Date: 28-02-2012
DOI: 10.1021/MA202673Q
Multisegmented polymers via step-growth and RAFT miniemulsion polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1PY01163D
Abstract: We report a method to efficiently prepare multisegmented polymers via a combination of step-growth (SG) and reversible addition-fragmentation chain transfer (RAFT) polymerization.
Ultrathin Monomolecular Films and Robust Assemblies Based on Cyclic Catechols
Publisher: American Chemical Society (ACS)
Date: 12-01-2017
DOI: 10.1021/ACS.LANGMUIR.6B03419
Abstract: We introduce a newly designed catechol-based compound and its application for the preparation of homogeneous monomolecular layers as well as for robust assemblies on various substrates. The precisely defined cyclic catechol material (CyCat) was prepared from ortho-dimethoxybenzene in a phenolic resin-like synthesis and subsequent deprotection, featuring molecules with up to 32 catechol units. The CyCat's chemical structure was carefully assessed via matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF), proton nuclear magnetic resonance (
A Novel Photoresponsive Azobenzene-Containing Miktoarm Star Polymer: Self-Assembly and Photoresponse Properties
Publisher: American Chemical Society (ACS)
Date: 21-05-2014
DOI: 10.1021/MA500254P
Visualizing the efficiency of rapid modular block copolymer construction
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0PY00189A
Flow Photochemistry for Single‐Chain Polymer Nanoparticle Synthesis
Publisher: Wiley
Date: 23-11-2020
Abstract: Single chain polymer nanoparticles (SCNP) are an attractive polymer architecture that provides functions seen in folded biomacromolecules. The generation of SCNPs, however, is limited by the requirement of a high dilution chemical step, necessitating the use of large reactors to produce processable quantities of material. Herein, the chemical folding of macromolecules into SCNPs is achieved in both batch and flow photochemical processes by the previously described photodimerization of anthracene units in polymethylmethacrylate (100 kDa) under UV irradiation at 366 nm. When employing flow chemistry, the irradiation time is readily controlled by tuning the flow rates, allowing for the precise control over the intramolecular collapse process. The flow system provides a route at least four times more efficient for SCNP formation, reaching higher intramolecular cross‐linking ratios five times faster than batch operation.
An Access Route to Polyferrocenes via Modular Conjugation
Publisher: Wiley
Date: 17-02-2011
A Study into the Stability of 3,6-Dihydro-2H-thiopyran Rings: Key Linkages in the RAFT Hetero-Diels−Alder Click Concept
Publisher: American Chemical Society (ACS)
Date: 14-10-2008
DOI: 10.1021/MA8013959
Cover Feature: Spatially‐Resolved Multiple Metallopolymer Surfaces by Photolithography (Chem. Eur. J. 71/2018)
Publisher: Wiley
Date: 06-12-2018
Chemiluminescent self-reported unfolding of single-chain nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CC00068C
Abstract: We demonstrate the light-induced, crosslinker mediated collapse of linear polymer chains into single-chain nanoparticles (SCNPs) capable of self-reporting their unfolding.
An efficient avenue to poly(styrene)‐block‐poly(ε‐caprolactone) polymers via switching from RAFT to hydroxyl functionality: Synthesis and characterization
Publisher: Wiley
Date: 13-10-2010
DOI: 10.1002/POLA.24299
Light induced DNA–protein conjugation
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC43291B
Abstract: DNA was modified with a photo-reactive caged diene allowing for the modification of dienophile containing proteins under mild irradiation conditions to afford fully functional DNA-protein conjugates.
Search for Alternative Two‐Step‐Absorption Photoinitiators for 3D Laser Nanoprinting
Publisher: Wiley
Date: 04-12-2022
Abstract: Recent studies have opened the door to a new generation of photoinitiators for 3D laser nanoprinting. Therein, the simultaneous absorption of two photons, commonly referred to as two‐photon absorption, is replaced by the sequential absorption of two photons in two consecutive one‐photon absorption processes. This process has been termed two‐step absorption. Importantly, two‐step absorption can be accomplished by inexpensive compact low‐power continuous‐wave blue laser diodes instead of femtosecond laser systems in the red spectral region. Red‐shifting the second absorption step with respect to the first one results in an and‐type optical nonlinearity based on two‐color two‐step absorption. Herein, alternatives are systematically explored to the few already reported one‐ and two‐color two‐step‐absorption photoinitiators, including the search for photoinitiators that can be excited by one‐color two‐step absorption and be de‐excited by a disparate laser color.
Chain-length-dependent termination in radical polymerization: Subtle revolution in tackling a long-standing challenge
Publisher: Elsevier BV
Date: 11-2009
Phenanthroline—A Versatile Ligand for Advanced Functional Polymeric Materials
Publisher: Wiley
Date: 07-11-2018
Abstract: The controlled incorporation of phenanthroline moieties into polymers is introduced, demonstrating their application as metal-ion complexing ligands for the construction of advanced macromolecular structures. Specifically, two phenanthroline-containing monomers based on acrylate and styrene functionalities, were synthesized. Each monomer was readily copolymerized with either N,N-dimethylacrylamide or styrene via nitroxide-mediated polymerization, resulting in narrowly distributed polar or non-polar copolymers. To demonstrate the versatility of the established polymer systems, the polar polymer was employed for transition metal induced single-chain nanoparticle formation, verified by diffusion-ordered NMR and UV/Vis spectroscopy. Furthermore, the non-polar polymer allows facile incorporation of lanthanide ions, creating luminescent metallo-polymers, in-depth characterized by advanced photophysical experiments and 2D NMR measurements.
Accessing Quantitative Degrees of Functionalization on Solid Substrates via Solid-State NMR Spectroscopy
Publisher: American Chemical Society (ACS)
Date: 16-03-2010
DOI: 10.1021/MA100149P
Es ist im Kleingedruckten: Löschbare dreidimensionale lasergedruckte Mikro‐ und Nanostrukturen
Publisher: Wiley
Date: 23-01-2020
Green chain-shattering polymers based on a self-immolative azobenzene motif
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5PY01937K
Abstract: A chain-shattering polymer system consisting of nontoxic, partially renewable resource-based monomers via acyclic diene metathesis (ADMET) chemistry is introduced.
Recent Advances in the Kinetics of Reversible Addition Fragmentation Chain-Transfer Polymerization
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/CH02042
Regioisomerism in Symmetric Dimethyl Dialdehydes Dictates their Photochemical Reactivity
Publisher: American Chemical Society (ACS)
Date: 24-06-2022
Abstract: We herein report the first light-driven selective monoderivatization (desymmetrization) of two chemically equivalent carbonyl groups in a single chromophore. By comparing of four symmetric regioisomers, featuring two equivalent
A Detailed Investigation of the Free Radical Copolymerization Behavior of n-Butyl Acrylate Macromonomers
Publisher: American Chemical Society (ACS)
Date: 04-08-2011
DOI: 10.1021/MA201345M
Ambient Temperature Ligation of Diene Functional Polymer and Peptide Strands onto Cellulose via Photochemical and Thermal Protocols
Publisher: Wiley
Date: 06-04-2014
Abstract: In the present contribution, two novel ambient temperature avenues are introduced to functionalize solid cellulose substrates in a modular fashion with synthetic polymer strands (poly(trifluoro ethyl methacrylate), PTFEMA, Mn = 4400 g mol(-1) , Đ = 1.18) and an Arg-Gly-Asp (RGD) containing peptide sequence. Both protocols rely on a hetero Diels-Alder reaction between an activated thiocarbonyl functionality and a diene species. In the first-thermally activated-protocol, the cellulose features surface-expressed thiocarbonylthio compounds, which readily react with diene terminal macromolecules at ambient temperature. In the second protocol, the reactive ene species are photochemically generated based on a phenacyl sulfide-decorated cellulose surface, which upon irradiation expresses highly reactive thioaldehyde species. The generated functional hybrid surfaces are characterized in-depth via ToF-SIMS and XPS analysis, revealing the successful covalent attachment of the grafted materials, including the spatially resolved patterning of both synthetic polymers and peptide strands using the photochemical protocol. The study thus provides a versatile platform technology for solid cellulose substrate modification via efficient thermal and photochemical ligation strategies.
Counting the Clicks in Fluorescent Polymer Networks
Publisher: Wiley
Date: 14-04-2018
Abstract: We introduce a fluorescence-based methodology enabling the quantification of ligation points in photochemically prepared polymer networks. Well-defined α,ω-tetrazole-capped polymer strands prepared via RAFT polymerization are crosslinked under UV irradiation by a trimaleimide via nitrile imine mediated tetrazole-ene cycloaddition. Thus, for each linkage point a fluorescent pyrazoline ring is formed, resulting in fluorescent networks, which are degradable by aminolysis of the trithiocarbonate functionalities, leading to soluble fragments. The fluorescence emission of the soluble network fragments correlates directly with the number of pyrazoline moieties originally present in the network, thus providing a direct measure of the number of ligation points constituting the network. The herein introduced strategy based on a fluorescence readout is a powerful yet simple approach to quantify network formation processes applicable to a wide class of polymers accessible via RAFT.
2D laser lithography on silicon substrates via photoinduced copper-mediated radical polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CC08444G
Abstract: A 2D laser lithography protocol for controlled grafting of polymer brushes in a single-step is presented.
A bioinspired light induced avenue for the design of patterned functional interfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3TB21317J
Enzyme‐Degradable 3D Multi‐Material Microstructures
Publisher: Wiley
Date: 07-10-2020
Quantification of Grafting Densities Achieved via Modular Grafting-to Approaches onto Divinylbenzene Microspheres
Publisher: Wiley
Date: 22-06-2010
Discussion on “Aperiodic Copolymers”
Publisher: American Chemical Society (ACS)
Date: 08-12-2015
DOI: 10.1021/ACSMACROLETT.5B00758
Abstract: In a recent Viewpoint (
Palladium-containing polymers via a combination of RAFT and triazole chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY20242E
Critically evaluated rate coefficients in radical polymerization – 7. Secondary-radical propagation rate coefficients for methyl acrylate in the bulk
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3PY00774J
Abstract: Benchmark propagation rate coefficient ( k p ) data for the radical polymerization of methyl acrylate are provided.
Chapter 5: RAFT Polymerization: Mechanistic Considerations
Publisher: Wiley
Date: 29-10-2021
Mass spectrometry as a tool to advance polymer science
Publisher: Springer Science and Business Media LLC
Date: 06-03-2020
Just Add Salt: A Mass Spectrometric Analysis Method for Imaging Anion‐Exchanged Poly(Ionic Liquid)s
Publisher: Wiley
Date: 29-08-2016
Abstract: We report the first mass spectrometric analysis of poly(ionic liquid)s (PILs) containing weakly coordinating anions introduced by a fast, simple, and quantitative postmodification method on the ex le of the hydrophilic, well-defined poly(vinylbenzylpyridinium chloride) p([VBPy]Cl) species, analyzed with an in-source collision induced dissociation-Orbitrap mass spectrometry (MS) protocol. Using the MS approach allows for the precise structural elucidation of ion-exchanged p([VBPy]Cl) utilizing AgX (X = NO
Fluorescence-Readout as a Powerful Macromolecular Characterisation Tool
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3SC04052F
Installing lactone chain termini during photoinduced polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY00457A
Abstract: We exploit the Thorpe–Ingold effect as a spontaneous end group transformation method during photo-induced polymerization of methacrylates using the functional (2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropio-phenone) species as radical photoinitiator.
Transformation of macromonomers into ring‐opening polymerization macroinitiators: A detailed initiation efficiency study
Publisher: Wiley
Date: 11-03-2012
DOI: 10.1002/POLA.26011
Two-colour light activated covalent bond formation
Publisher: Springer Science and Business Media LLC
Date: 26-05-2022
DOI: 10.1038/S41467-022-30002-6
Abstract: We introduce a photochemical bond forming system, where two colours of light are required to trigger covalent bond formation. Specifically, we exploit a visible light cis / trans isomerization of chlorinated azobenzene, which can only undergo reaction with a photochemically generated ketene in its cis state. Detailed photophysical mapping of the reaction efficiencies at a wide range of monochromatic wavelengths revealed the optimum irradiation conditions. Subsequent small molecule and polymer ligation experiments illustrated that only the application of both colours of light affords the reaction product. We further extend the functionality to a photo reversible ketene moiety and translate the concept into material science. The presented reaction system holds promise to be employed as a two-colour resist.
Intrinsically Fluorescent, Stealth Polypyrazoline Nanoparticles with Large Stokes Shift for In Vivo Imaging
Publisher: Wiley
Date: 05-08-2018
Abstract: Recent advances in super-resolution microscopy and fluorescence bioimaging allow exploring previously inaccessible biological processes. To this end, there is a need for novel fluorescent probes with specific features in size, photophysical properties, colloidal and optical stabilities, as well as biocompatibility and ability to evade the reticuloendothelial system. Herein, novel fluorescent nanoparticles are introduced based on an inherently fluorescent polypyrazoline (PPy) core and a polyethylene glycol (PEG) shell, which address all aforementioned challenges. Synthesis of the PPy-PEG hiphilic block copolymer by phototriggered step-growth polymerization is investigated by NMR spectroscopy, size-exclusion chromatography, and mass spectrometry. The corresponding nanoparticles are characterized for their luminescent properties and hydrodynamic size in various aqueous environments (e.g., cell culture media). PPy nanoparticles particularly exhibit a large Stokes shift (Δλ = 160 nm or Δν > 7000 cm
Studying the polymerization initiation efficiency of acetophenone-type initiators via PLP-ESI-MS and femtosecond spectroscopy
Publisher: Royal Society of Chemistry (RSC)
Date: 29-04-2014
DOI: 10.1039/C4PY00418C
Tailoring the Mechanical Properties of 3D Microstructures Using Visible Light Post‐Manufacturing
Publisher: Wiley
Date: 03-06-2019
Abstract: The photochemistry of anthracene, a new class of photoresist for direct laser writing, is used to enable visible-light-gated control over the mechanical properties of 3D microstructures post-manufacturing. The mechanical and viscoelastic properties (hardness, complex elastic modulus, and loss factor) of the microstructures are measured over the course of irradiation via dynamic mechanical analysis on the nanoscale. Irradiation of the microstructures leads to a strong hardening and stiffening effect due to the generation of additional crosslinks through the photodimerization of the anthracene functionalities. A relationship between the loss of fluorescence-a consequence of the photodimerization-and changes in the mechanical properties is established. The fluorescence thus serves as a proxy read-out for the mechanical properties. These photoresponsive microstructures can potentially be used as "mechanical blank slates": their mechanical properties can be readily adjusted using visible light to serve the demands of different applications and read out using their fluorescence.
An in-depth analysis approach enabling precision single chain nanoparticle design
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY01045F
Abstract: The synthesis of single chain nanoparticles (SCNPs) is a vibrant field in macromolecular science. However, to achieve an in-depth understanding of the nature of intramolecular polymer folding, a step-change in the methodologies for SCNP analysis is required.
Facile Access to Chain Length Dependent Termination Rate Coefficients via Reversible Addition−Fragmentation Chain Transfer (RAFT) Polymerization: Influence of the RAFT Agent Structure
Publisher: American Chemical Society (ACS)
Date: 09-03-2004
DOI: 10.1021/MA0358428
DNA labelling in live cells via visible light-induced [2+2] photocycloaddition
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3CC00817G
Abstract: Styrylquinoxaline (SQ)-modified DNA is labelled with SQ-modified dyes in live HeLa cells via [2+2] photocycloaddition using visible light irradiation.
Kinetic investigations of reversible addition fragmentation chain transfer polymerizations: Cumyl phenyldithioacetate mediated homopolymerizations of styrene and methyl methacrylate
Publisher: American Chemical Society (ACS)
Date: 29-09-2001
DOI: 10.1021/MA010349M
Photoswitchable block copolymers based on main chain α-bisimines
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2PY00994C
Abstract: We introduce linear diblock copolymers (BCPs) consisting of readily accessable and photoswitchable α-bisimine units in the polymer backbone.
Thioketone spin traps as mediating agents for free radical polymerization processes
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B515561D
Abstract: Thioketones are demonstrated to be suitable agents for controlling free radical polymerization processes: the polymerizations carry (pseudo) living characteristics indicating that the control process is induced by a persistent radical effect.
Design and Synthesis of Triblock Copolymers for Creating Complex Secondary Structures by Orthogonal Self-Assembly
Publisher: American Chemical Society (ACS)
Date: 08-12-2015
Propagation rate coefficients of isobornyl acrylate, tert‐butyl acrylate and 1‐ethoxyethyl acrylate: A high frequency PLP‐SEC study
Publisher: Wiley
Date: 27-10-2009
DOI: 10.1002/POLA.23706
Abstract: Pulsed laser polymerization (PLP) coupled to size exclusion chromatography (SEC) is considered to be the most accurate and reliable technique for the determination of absolute propagation rate coefficients, k p . Herein, k p data as a function of temperature were determined via PLP‐SEC for three acrylate monomers that are of particular synthetic interest (e.g., for the generation of hiphilic block copolymers). The high‐ T g monomer isobornyl acrylate ( i BoA) as well as the precursor monomers for the synthesis of hydrophilic poly(acrylic acid), tert ‐butyl acrylate ( t BuA), and 1‐ethoxyethyl acrylate (EEA) were investigated with respect to their propagation rate coefficient in a wide temperature range. By application of a 500 Hz laser repetition rate, data could be obtained up to a temperature of 80 °C. To arrive at absolute values for k p , the Mark‐Houwink parameters of the polymers have been determined via on‐line light scattering and viscosimetry measurements. These read: K = 5.00 × 10 5 dL g −1 , a = 0.75 (p i BoA), K = 19.7 × 10 5 dL g −1 , a = 0.66 (p t BA) and K = 1.53 × 10 5 dL g −1 , a = 0.85 (pEEA). The bulky i BoA monomer shows the lowest propagation rate coefficient among the three monomers, while EEA is the fastest. The activation energies and Arrhenius factors read: ( i BoA): log( A /L mol −1 s −1 ) = 7.05 and E A = 17.0 kJ mol −1 ( t BuA): log( A /L mol −1 s −1 ) = 7.28 and E A = 17.5 kJ mol −1 and (EEA): log( A /L mol −1 s −1 ) = 6.80 and E A = 13.8 kJ mol −1 . © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6641–6654, 2009
Polymer Functional Nanodiamonds by Light-Induced Ligation
Publisher: American Chemical Society (ACS)
Date: 19-02-2016
Folding polymer chains with visible light
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CC01054D
Abstract: A simple and versatile tool for generating fluorescent single chain polymer nanoparticles with visible light.
Light-Stabilized Dynamic Materials
Publisher: American Chemical Society (ACS)
Date: 26-06-2019
DOI: 10.1021/JACS.9B05092
Abstract: The light-responsive adaptation of polymer materials typically requires different wavelengths or additional heat to induce reversible covalent bond formation and dissociation. Here, we bypass the use of invasive triggers by introducing light-stabilized dynamic materials that can undergo a repeatable change in topology from a covalently cross-linked material into a liquid polymer formulation by switching one visible light source on-and-off without the need for any additional triggers. Specifically, we exploit the photo-Diels-Alder reaction of triazolinediones with naphthalenes as a dynamic covalent cross-linking platform that enables green light-induced network formation, while the cross-linked material collapses through spontaneous cycloreversion upon standing in the dark at ambient temperature. Importantly, the covalent cross-links remain stabilized for as long as visible light is present, thereby retaining the material's structural integrity. This enables their potential use in an array of light-directed applications whereby network properties such as stiffness can be tuned by the mildest trigger of all: darkness.
Chain Transfer in Degenerative RAFT Polymerization Revisited: A Comparative Study of Literature Methods
Publisher: Wiley
Date: 08-02-2016
The future of reversible addition fragmentation chain transfer polymerization
Publisher: Wiley
Date: 25-07-2008
DOI: 10.1002/POLA.22866
Flow Photochemistry for Single‐Chain Polymer Nanoparticle Synthesis
Publisher: Wiley
Date: 23-11-2020
Abstract: Single chain polymer nanoparticles (SCNP) are an attractive polymer architecture that provides functions seen in folded biomacromolecules. The generation of SCNPs, however, is limited by the requirement of a high dilution chemical step, necessitating the use of large reactors to produce processable quantities of material. Herein, the chemical folding of macromolecules into SCNPs is achieved in both batch and flow photochemical processes by the previously described photodimerization of anthracene units in polymethylmethacrylate (100 kDa) under UV irradiation at 366 nm. When employing flow chemistry, the irradiation time is readily controlled by tuning the flow rates, allowing for the precise control over the intramolecular collapse process. The flow system provides a route at least four times more efficient for SCNP formation, reaching higher intramolecular cross‐linking ratios five times faster than batch operation.
Critically Evaluated Rate Coefficients in Radical Polymerization – 8. Propagation Rate Coefficients for Vinyl Acetate in Bulk
Publisher: Wiley
Date: 26-09-2016
Imaging Single-Chain Nanoparticle Folding via High-Resolution Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 27-12-2016
DOI: 10.1021/JACS.6B10952
Abstract: Herein, we introduce the first approach to map single-chain nanoparticle (SCNP) folding via high-resolution electrospray ionization mass spectrometry (ESI MS) coupled with size exclusion chromatography. For the first time, the successful collapse of polymeric chains into SCNPs is imaged by characteristic mass changes, providing detailed mechanistic information regarding the folding mechanism. As SCNP system we employed methyl methacrylate (MMA) statistically copolymerized with glycidyl methacrylate (GMA), resulting in p(MMA-stat-GMA), subsequently collapsed by using B(C
Critical Assessment of the Application of Multidetection SEC and AF4 for the Separation of Single-Chain Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 20-10-2020
DOI: 10.1021/ACSMACROLETT.0C00519
Abstract: The intramolecular chain collapse of linear precursors with systematic variation of molar mass and ligation group density (5, 15, and 30 mol %) into single-chain nanoparticles (SCNPs) was studied by two different separation approaches. The efficiency of size exclusion chromatography with quadruple detection (SEC-D4) was compared to asymmetrical field flow fractionation hyphenated to quintuple detection (AF4-D5) in organic solvent. The application of the unique combination of advanced detection to different separation principles opens up the opportunity to critically evaluate the determination of molar masses and different types of radii for an in-depth understanding of the structural properties affected by the internal folding process. This is achieved by a detailed comparison of assets, drawbacks, and limitations of these approaches based on the systematical screening of different chain lengths and sizes of the precursors and the SCNPs. Furthermore, an alternative strategy for quantitative determination of intramolecular ligation density by a combination of AF4 and UV detection is introduced.
Red-Light Driven Photocatalytic Oxime Ligation for Bioorthogonal Hydrogel Design
Publisher: American Chemical Society (ACS)
Date: 18-12-2020
DOI: 10.1021/ACSMACROLETT.0C00767
Abstract: Light-mediated polymer cross-linking is frequently employed for the preparation of hydrogels for biomedical applications. However, most photopolymerization processes require activation by UV light or short wavelength visible light, which are highly absorbed by skin and tissue, limiting their uses in transdermal initiation. Herein, we introduce red light-enabled oxime ligation by the in situ photogeneration of aldehydes, which rapidly react with hydroxylamines. We demonstrate efficient polymer cross-linking behind a dermal tissue model by red light initiation. Optimization of the photopolymerization conditions allows for 3D encapsulation of human foreskin fibroblasts with good cell viability postencapsulation.
Modulation of the Thermoresponsive Behavior of Poly(N,N‐diethylacrylamide) via Cyclodextrin Host/Guest Interactions
Publisher: Wiley
Date: 24-07-2013
Abstract: The modulation of the cloud point of aqueous poly(N,N-diethylacrylamide) solutions via the formation of supramolecular cyclodextrin complexes with hydrophobic end groups, namely adamantyl, tert-butyl phenyl and azobenzene, synthesized via RAFT polymerization is described. The dependence of the apparent cloud points after cyclodextrin complexation is investigated with respect to the type and quantity of the guest end group, the polymer chain length and the cyclodextrin/end group ratio. Furthermore, the effect is reversed via the addition of guest molecules or via biocompatible enzymatic degradation of the cyclodextrins entire.
Synthesis of poly(vinyl alcohol) combs via MADIX/RAFT polymerization
Publisher: Elsevier BV
Date: 02-2006
Modeling Termination Kinetics of Non-Stationary Free-Radical Polymerizations
Publisher: Wiley
Date: 04-2001
DOI: 10.1002/1521-3919(20010401)10:4<209::AID-MATS209>3.0.CO;2-Z
Photolithographic Patterning of 3D‐Formed Polycarbonate Films for Targeted Cell Guiding
Publisher: Wiley
Date: 18-03-2015
Abstract: A facile photolithographic platform for the design of cell-guiding polymeric substrates is introduced. Specific areas of the substrate are photo-deactivated for the subsequent growth of bioresistant polymer brushes, creating zones for cell proliferation, and protein adhesion.
Laser induced marking of polymer chains with radical spin traps
Publisher: Wiley
Date: 19-03-2008
Cooperative Network Formation via Two‐Colour Light‐Activated λ‐Orthogonal Chromophores
Publisher: Wiley
Date: 24-07-2023
Abstract: Independently addressing photoreactive sites within one molecule with two colours of light is a formidable challenge. Here, we combine two sequence independent λ‐orthogonal chromophores in one heterotelechelic dilinker molecule, to exploit their disparate reactivity utilizing the same reaction partner, a maleimide‐containing polymer. We demonstrate that polymer network formation only proceeds if two colours of light are employed. Upon single colour irradiation, linker‐decorated post‐functionalized polymers are generated at either wavelength and in either sequence. Network formation, however, is only achieved by sequential or simultaneous two colour irradiation. The herein introduced photoreactive system demonstrates the power of wavelength orthogonal chemistry in macromolecular synthesis.
Tuning the photoreactivity of photocycloaddition by halochromism
Publisher: CSIRO Publishing
Date: 25-07-2022
DOI: 10.1071/CH22103
Abstract: Harnessing the power of light for chemical transformation is a long-standing goal in organic synthesis, materials fabrication and engineering. Amongst all photochemical reactions, [2 + 2] photocycloadditions are inarguably the most important and most frequently used. These photoreactions have green characteristics by enabling new bond formation in a single step procedure under light irradiation, without the need for heat or chemical catalysis. More recently, substantial progress has been made in red-shifting the activation wavelength of photocycloadditions in response to research trends moving towards green and sustainable processes, and advanced applications in biological environments. In the past 5 years, our team has further expanded the toolbox of photocycloaddition reactions that can be triggered by visible light. In our exploration of photochemical reactivity, we found that reactivity is often red-shifted compared to the substrate’s absorption spectrum. Our efforts have resulted in red-shifted photochemical reactions, providing some of the lowest energy – and catalyst-free – photo-activated [2 + 2] cycloadditions (up to 550 nm). More recently, we introduced an additional level of control over such finely wavelength gated reactions by altering the pH of the reaction environment, thus exploiting halochromic effects to enhance or impede the photoreactivity of red-shifted [2 + 2] photocycloaddition reactions. In this account, we discuss the current state of halochromically regulated photochemical reactions and their potential in soft matter materials on selected ex les.
Investigating the Photochemistry of Spiropyran Metal Complexes with Online LED-NMR
Publisher: American Chemical Society (ACS)
Date: 26-10-2019
DOI: 10.1021/ACS.INORGCHEM.9B02547
Abstract: As one of the best studied photoswitches, spiropyrans (SPs) have attracted significant interest in the scientific community. Among the many stimuli to alter the isomerization into the merocyanine (MC) isomer, such as temperature, pH, solvent polarity, redox potential, or mechanical force, the ability of the MC form to act as a ligand site for metal complexation has recently raised new attention. We herein synthesize hitherto undescribed coordination compounds of 8-methoxy-1',3',3'-trimethyl-6-nitrospiro-[chromene-2,2'-indoline] with s-block ([Ca(MC)
Gezielte Spaltung von durch direktes Laserschreiben hergestellten Mikrostrukturen
Publisher: Wiley
Date: 13-04-2017
Using precision polymer chemistry for plastics traceability and governance
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2PY01180H
Abstract: Resolving the anonymity of plastic materials is critical for safeguarding the well-being of our natural environments and human health.
The reversible addition‐fragmentation chain transfer process and the strength and limitations of modeling: Comment on “the magnitude of the fragmentation rate coefficient”
Publisher: Wiley
Date: 08-2003
DOI: 10.1002/POLA.10854
A versatile and straightforward process to turn plastics into antibacterial materials
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1PY01344K
Abstract: Antibacterial activity without cell cytotoxicity is conferred to common plastic materials by dispersion of hiphilic cationic methacrylate-based block copolymers (0.5–2 wt%), while maintaining the mechanical properties of the materials.
Synthesis of semi-biodegradable crosslinked microspheres for the delivery of 1,25 dihydroxyvitamin D3 for the treatment of hepatocellular carcinoma
Publisher: Elsevier BV
Date: 05-2007
Complications in the 355 nm Pulsed-Laser Polymerization ofN-Vinylcarbazole
Publisher: Wiley
Date: 09-2001
DOI: 10.1002/1521-3927(20010901)22:13<1035::AID-MARC1035>3.0.CO;2-Y
Nahinfrarotlicht‐induzierte radikalische Polymerisation in Wasser
Publisher: Wiley
Date: 06-09-2022
Abstract: Wir stellen eine auf Goldnanostäbchen (AuNR) basierende Methode vor, um eine radikalische Polymerisation in Wasser mit Nahinfrarotlicht (800 nm) zu induzieren. Der Prozess nutzt die photothermische Umwandlung in AuNR und die anschließende Wärmeübertragung auf einen Radikalinitiator (hier Azobisisobutyronitril) für die primäre Radikalbildung. Es wurde ein breites Spektrum an Reaktionsbedingungen untersucht, wobei die Kontrolle über das Molekulargewicht und den Reaktionsumsatz von Dimethylacrylamidpolymeren mit Hilfe der kernmagnetischen Resonanzspektroskopie nachgewiesen wurde. Wir untermauern unsere experimentellen Daten mit einer Finite‐Elemente‐Simulation des räumlich‐zeitlichen Temperaturprofils in der Umgebung der AuNR direkt nach der Anregung durch Femtosekunden‐Laserpulse. Wir weisen nach, dass die Polymerisation, aufgrund erhöhter Eindringtiefe des Nahinfrarotlichts, durch biologisches Gewebe induziert werden kann. Wir sind der Meinung, dass der vorgestellte Initiierungsmechanismus in wässrigen Systemen vielversprechend für die radikale Polymerisation in biologischen Umgebungen, einschließlich Zellen, ist.
Visualization of poly(methyl methacrylate) (PMMA) grafts on cellulose via high-resolution FT-IR microscopy imaging
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00338K
Quantitative Analysis of Step-Growth Polymers by Size Exclusion Chromatography
Publisher: American Chemical Society (ACS)
Date: 15-08-2016
Simultaneous reversible addition fragmentation chain transfer and ring‐opening polymerization
Publisher: Wiley
Date: 27-03-2008
DOI: 10.1002/POLA.22647
Determining the Mark–Houwink parameters of nitrile rubber: a chromatographic investigation of the NBR microstructure
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3PY00580A
Scalable Synthesis of Sequence‐Defined Oligomers via Photoflow Chemistry
Publisher: Wiley
Date: 20-02-2019
An In-Depth Mechanistic Investigation of the Radical Initiation Behavior of Monoacylgermanes
Publisher: American Chemical Society (ACS)
Date: 09-11-2017
Interpolymer radical coupling: A toolbox complementary to controlled radical polymerization
Publisher: Elsevier BV
Date: 07-2012
Stepwise Light-Induced Dual Compaction of Single-Chain Nanoparticles
Publisher: Wiley
Date: 04-07-2017
Abstract: A photochemical strategy for the sequential dual compaction of single polymer chains is introduced. Two photoreactive methacrylates, with side chains bearing either a phenacyl sulfide (PS) or an α-methylbenzaldehyde (photoenol, PE) moiety, are selectively incorporated by one-pot iterative reversible-addition fragmentation chain transfer copolymerization into the outer blocks of a well-defined poly(methyl methacrylate) based ABC triblock copolymer possessing a nonfunctional spacer block (M
A New Class of Materials: Sequence‐Defined Macromolecules and Their Emerging Applications
Publisher: Wiley
Date: 02-01-2019
Abstract: Emerging applications of a new class of materials, sequence-defined macromolecules, are explored. Such molecularly highly defined macromolecules require stringent synthesis and purification procedures, yet offer unprecedented application possibilities. The first ex les of molecular data storage and related technologies are already starting to emerge today. From a more fundamental point of view, such macromolecules offer a unique opportunity to determine quantitative structure-property relationships (QSPR), which critically aids in designing materials with applications ranging from catalysis to artificial enzymes.
A simplified approach to thermally activated delayed fluorescence (TADF) bipolar host polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2PY00511E
Abstract: Herein, we compare a series of solution-processible TADF polymers with different host pendant groups to achieve balanced charge transport properties through the combination of unipolar co-hosts.
Synthesis of water-soluble homo- and block-copolymers by RAFT polymerization under γ-irradiation in aqueous media
Publisher: Elsevier BV
Date: 09-2010
Hyphenation of size-exclusion chromatography to mass spectrometry for precision polymer analysis – a tutorial review
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9PY00370C
Abstract: Herein we demonstrate how SEC-ESI-MS can be used to analyze complex polymers, a significant challenge in contemporary polymer chemistry.
Determination of vinyl acetate propagation rate coefficients via high frequency pulsed laser polymerization
Publisher: Walter de Gruyter GmbH
Date: 12-2009
DOI: 10.1515/EPOLY.2009.9.1.931
Abstract: New data on the propagation rate coefficient, k p , of vinyl acetate (VAc) are obtained via the IUPAC recommended method of pulsed laser polymerization - size exclusion chromatography (PLP-SEC) operated at 500 Hz laser repetition rate. An apparent dependency of the experiment’s outcome on the laser pulsing rate is identified with k p being about 25 % larger at 500 Hz compared to 100 Hz. The temperature dependence of k p was determined to fit ln k p = 17.12 - 2621 K/ T data is in generally good agreement with literature values when the previous underestimation of k p by 100 Hz laser pulsing experiments is taken into account.
Cleaving Direct‐Laser‐Written Microstructures on Demand
Publisher: Wiley
Date: 13-04-2017
Abstract: Using an advanced functional photoresist we introduce direct-laser-written (DLW) 3D microstructures capable of complete degradation on demand. The networks consist exclusively of reversible bonds, formed by irradiation of a phenacyl sulfide linker, giving disulfide bonds in a radical-free step-growth polymerization via a reactive thioaldehyde. The bond formation was verified in solution by ESI-MS. To induce cleavage, dithiothreitol causes a thiol-disulfide exchange, erasing the written structure. The mild cleavage of the disulfide network is highly orthogonal to other, for ex le, acrylate-based DLW structures. To emphasize this aspect, DLW structures were prepared incorporating reversible structural elements into a non-reversible acrylate-based standard scaffold, confirming subsequent selective cleavage. The high lateral resolution achievable was verified by the preparation of well-defined line gratings with line separations of down to 300 nm.
Termination kinetics of styrene free-radical polymerization studied by time-resolved pulsed laser experiments
Publisher: Wiley
Date: 02-2000
DOI: 10.1002/(SICI)1521-3935(20000201)201:4<464::AID-MACP464>3.0.CO;2-4
Using the reversible addition–fragmentation chain transfer process to synthesize core‐crosslinked micelles
Publisher: Wiley
Date: 10-02-2006
DOI: 10.1002/POLA.21328
Hetero Diels–Alder Chemistry for the Functionalization of Single‐Walled Carbon Nanotubes with Cyclopentadienyl End‐Capped Polymer Strands
Publisher: Wiley
Date: 18-03-2013
Abstract: Single-walled carbon nanotubes (SWCNTs) are pre-functionalized with a pyridinyl-based dithioester to undergo a hetero Diels-Alder (HDA) reaction with cyclopentadienyl end-capped poly(methyl)methacrylate (Mn = 2700 g mol(-1) , PDI = 1.14). Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis (EA), and X-ray photoelectron spectroscopy (XPS) evidence the success of the grafting process. The estimated resulting grafting density (from XPS and EA) via the HDA reaction increases by a factor of more than two (0.0774 chains·nm(-2) via XPS) compared with typical values obtained via a direct cyclopentadiene driven Diels-Alder conjugation onto non-functional SWCNTs under similar conditions.
Quantitative Comparison of the Mesitoyl vs the Benzoyl Fragment in Photoinitiation: A Question of Origin
Publisher: American Chemical Society (ACS)
Date: 30-03-2011
DOI: 10.1021/MA2001977
Emerging Investigators 2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY90042F
Abstract: This themed issue of Polymer Chemistry highlights the work of emerging investigators in polymer chemistry. Editor-in-Chief Christopher Barner–Kowollik introduces the issue.
Free-radical copolymerization of styrene and itaconic acid studied by1H NMR kinetic experiments
Publisher: Wiley
Date: 2001
DOI: 10.1002/1099-0518(20010301)39:5<656::AID-POLA1037>3.0.CO;2-9
Critically evaluated termination rate coefficients for free-radical polymerization: Experimental methods
Publisher: Elsevier BV
Date: 06-2005
The Next 100 Years of Polymer Science
Publisher: Wiley
Date: 29-07-2020
Termination Kinetics of Methyl Methacrylate Free-Radical Polymerization Studied by Time-Resolved Pulsed Laser Experiments
Publisher: American Chemical Society (ACS)
Date: 28-04-1998
DOI: 10.1021/MA971748D
Light-driven reversible surface functionalization with anthracenes: visible light writing and mild UV erasing
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6CC09897E
Abstract: We introduce a methodology to reversibly pattern planar surfaces via the light-induced dimerization of anthracenes, particularly involving a 9-triazolylanthracene motif.
Self-reporting visible light-induced polymer chain collapse
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9PY00834A
Abstract: We introduce a facile photoinduced self-reporting crosslinking methodology for the compaction of polymer chains in highly diluted solution.
Light-induced ligation of o-quinodimethanes with gated fluorescence self-reporting
Publisher: American Chemical Society (ACS)
Date: 15-04-2020
DOI: 10.1021/JACS.0C02002
Untapped toolbox of luminol based polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1PY00034A
Abstract: The present state of luminol based polymers is highlighted with the challenges and the respective strategies for the advancement of this versatile class of polymers.
Adaptable and Reprogrammable Surfaces
Publisher: Wiley
Date: 15-08-2019
Abstract: Establishing control over chemical reactions on interfaces is a key challenge in contemporary surface and materials science, in particular when introducing well-defined functionalities in a reversible fashion. Reprogrammable, adaptable and functional interfaces require sophisticated chemistries to precisely equip them with specific functionalities having tailored properties. In the last decade, reversible chemistries-both covalent and noncovalent-have paved the way to precision functionalize 2 or 3D structures that provide both spatial and temporal control. A critical literature assessment reveals that methodologies for writing and erasing substrates exist, yet are still far from reaching their full potential. It is thus critical to assess the current status and to identify avenues to overcome the existing limitations. Herein, the current state-of-the-art in the field of reversible chemistry on surfaces is surveyed, while concomitantly identifying the challenges-not only synthetic but also in current surface characterization methods. The potential within reversible chemistry on surfaces to function as true writeable memories devices is identified, and the latest developments in readout technologies are discussed. Finally, we explore how spatial and temporal control over reversible, light-induced chemistries has the potential to drive the future of functional interface design, especially when combined with powerful laser lithographic applications.
Photo-Induced Ligation of Acrylonitrile-Butadiene Rubber: Selective Tetrazole–Ene Coupling of Chain-End-Functionalized Copolymers of 1,3-Butadiene
Publisher: American Chemical Society (ACS)
Date: 29-07-2013
DOI: 10.1021/MA401154K
Fluorescence turn-on by photoligation – bright opportunities for soft matter materials
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2SC05403E
Abstract: Photochemical ligations that form fluorescent products provide valuable visual feedback for use in biology and material science.
RAFT-mediated polymerization and grafting of sodium 4-styrenesulfonate from cellulose initiated via gamma-radiation
Publisher: Elsevier BV
Date: 02-2009
Mechanistic Insights into the UV-Induced Radical Copolymerization of 1,3-Butadiene with Acrylonitrile
Publisher: American Chemical Society (ACS)
Date: 05-03-2013
DOI: 10.1021/MA4000896
Poly(vinyl alcohol) star polymers prepared via MADIX/RAFT polymerisationElectronic Supplementary Information (ESI) available: synthesis and NMR data of MADIX agents, polymerisation and analysis techni
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B404763J
Abstract: Poly(vinyl acetate) stars were prepared using MADIX/RAFT polymerisation mediated by xanthates. The polymerisation shows living characteristics with molecular weight increasing with conversion. The subsequent hydrolysis of these three and four arm stars led to the formation of poly(vinyl alcohol) stars.
Synthesis of amphiphilic block copolymers based on poly(dimethylsiloxane) via fragmentation chain transfer (RAFT) polymerization
Publisher: Elsevier BV
Date: 06-2004
Hybrid Photo-induced Copolymerization of Ring-Strained and Vinyl Monomers Utilizing Metal-Free Ring-Opening Metathesis Polymerization Conditions
Publisher: American Chemical Society (ACS)
Date: 08-10-2019
DOI: 10.1021/JACS.9B09025
Abstract: We introduce the hybrid copolymerization of two disparate monomer classes (vinyl monomers and ring-strained cyclic olefins) via living photopolymerization. The living character of the polymerization technique (metal-free photo-ROMP) is demonstrated by consecutive chain-extensions. Further, we propose a mechanism for the copolymerization and analyze the copolymer structure in detail by high-resolution mass spectrometry.
Action Plots in Action: In-Depth Insights into Photochemical Reactivity
Publisher: American Chemical Society (ACS)
Date: 03-12-2021
DOI: 10.1021/JACS.1C09419
Abstract: Predicting wavelength-dependent photochemical reactivity is challenging. Herein, we revive the well-established tool of measuring action spectra and adapt the technique to map wavelength-resolved covalent bond formation and cleavage in what we term "photochemical action plots". Underpinned by tunable lasers, which allow excitation of molecules with near-perfect wavelength precision, the photoinduced reactivity of several reaction classes have been mapped in detail. These include photoinduced cycloadditions and bond formation based on photochemically generated
Diels–Alder reactions for carbon material synthesis and surface functionalization
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3PY00232B
Spin fluorescence silencing enables an efficient thermally driven self-reporting polymer release system
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY01437F
Abstract: A self-reporting profluorescent release system driven by the thermo-reversible dynamic covalent ligation of chromophores to polymer chain, whose fluorescence is silenced by unpaired spins of nitroxides prior to release is introduced.
Simultaneously recorded photochemical action plots reveal orthogonal reactivity
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3CC03777K
DNA–Polymer Conjugates by Photoinduced RAFT Polymerization
Publisher: American Chemical Society (ACS)
Date: 08-11-2018
DOI: 10.1021/ACS.BIOMAC.8B01328
Abstract: Conventional grafting-to approaches to DNA-polymer conjugates are often limited by low reaction yields due to the sterically hindered coupling of a presynthesized polymer to DNA. The grafting-from strategy, in contrast, allows one to directly graft polymers from an initiator that is covalently attached to DNA. Herein, we report blue-light-mediated reversible addition-fragmentation chain-transfer (Photo-RAFT) polymerization from two different RAFT agent-terminated DNA sequences using Eosin Y as the photocatalyst in combination with ascorbic acid. Three monomer families (methacrylates, acrylates and acrylamides) were successfully polymerized from DNA employing Photo-RAFT polymerization. We demonstrate that the length of the grown polymer chain can be varied by altering the monomer to DNA-initiator ratio, while the self-assembly features of the DNA strands were maintained. In summary, we describe a convenient, light-mediated approach toward DNA-polymer conjugates via the grafting-from approach.
Stepwise Unfolding of Single‐Chain Nanoparticles by Chemically Triggered Gates
Publisher: Wiley
Date: 30-06-2016
Abstract: The orthogonal, stepwise, and order-independent unfolding of single-chain nanoparticles (SCNPs) is introduced as a key step towards actively controlling the folding dynamics of SCNPs. The SCNPs are compacted by multiple hydrogen bonds and host-guest interactions. Well-defined diblock (AB) and tetrablock (ABCD) copolymers are equipped with orthogonal recognition motifs via modular ligation along the lateral chain. Initially, single-chain folding of the diblock copolymer was induced by the host-guest complexation of benzo-21-crown-7 (B21C7, host) and a secondary ammonium salt (AS, guest), representing an efficient avenue for single-chain collapse. Next, both orthogonal Hamilton wedge (HW) and cyanuric acid (CA) as well as B21C7-AS motifs were employed to generate SCNPs based on the ABCD polymer system. Subsequently, the stepwise dual-gated and order-independent unfolding of the SCNPs was investigated by the addition of external stimuli. The folding and unfolding were explored by 1D (1) H NMR spectroscopy, dynamic light scattering (DLS), and diffusion-ordered NMR spectroscopy (DOSY).
Four component Passerini polymerization of bulky monomers under high shear flow
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CC02984C
Abstract: We introduce a four component Passerini polymerization utilizing sterically bulky isocyanide monomers.
In-Depth LCCC-(GELC)-SEC Characterization of ABA Block Copolymers Generated by a Mechanistic Switch from RAFT to ROP
Publisher: American Chemical Society (ACS)
Date: 20-12-2011
DOI: 10.1021/MA2022452
Living free-radical polymerization (reversible addition-fragmentation chain transfer) of 6-[4-(4 '-methoxyphenyl)phenoxy]hexyl methacrylate: A route to architectural control of side-chain liquid-crystal line polymers
Publisher: Wiley
Date: 08-08-2003
DOI: 10.1002/POLA.10894
Photo-Cross-Linkable Polymer Inks for Solution-Based OLED Fabrication
Publisher: American Chemical Society (ACS)
Date: 15-11-2019
Unraveling the Spontaneous Zwitterionic Copolymerization Mechanism of Cyclic Imino Ethers and Acrylic Acid
Publisher: American Chemical Society (ACS)
Date: 08-01-2018
Red light induced folding of single polymer chains
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CC05415A
Abstract: We pioneer the photochemical generation of single chain nanoparticles (SCNPs) at the to-date mildest reported wavelength of 625 nm by exploiting the photochemical uncaging of methylene blue protected amines.
Constructing star polymersvia modular ligation strategies
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00249J
Abstract: Over recent years, modular ligation reactions—some of which adhere to the click criteria—have enabled the synthesis of a variety of star polymers via efficient polymer–polymer conjugations. The copper catalyzed azide–alkyne cycloaddition (CuAAC), Diels–Alder (DA), and Hetero Diels–Alder (HDA) reactions are reviewed here in detail for the facile generation of various macromolecular star topologies.
Limitations of radical thiol‐ene reactions for polymer–polymer conjugation
Publisher: Wiley
Date: 08-03-2010
DOI: 10.1002/POLA.23933
Abstract: In this work, we report our findings on the use of radical thiol‐ene chemistry for polymer–polymer conjugation. The manuscript combines the results from the Preparative Macromolecular Chemistry group from the Karlsruhe Institute of Technology (KIT) and the Polymer Chemistry Research group from Ghent University (UGent), which allowed for an investigation over a very broad range of reaction conditions. In particular, thermal and UV initiation methods for the radical thiol‐ene process were compared. In the KIT group, the process was studied as a tool for the synthesis of star polymers by coupling multifunctional thiol core molecules with poly( n ‐butyl acrylate) macromonomers (MM), employing thermally decomposing initiators. The product purity and thus reaction efficiency was assessed via electrospray ionization mass spectrometry. Although the reactions with 10 or 5 equivalents of thiol with respect to macromonomer were successful, the coupling reaction with a one‐to‐one ratio of MM to thiol yielded only a fraction of the targeted product, besides a number of side products. A systematic parameter study such as a variation of the concentration and nature of the initiator and the influence of thiol‐to‐ene ratio was carried out. Further experiments with poly(styrene) and poly(isobornyl acrylate) containing a vinylic end group confirmed that thermal thiol‐ene conjugation is far from quantitative in terms of achieving macromolecular star formation. In parallel, the UGent group has been focusing on photo‐initiated thiol‐ene chemistry for the synthesis of functional polymers on one hand and block copolymers consisting of poly(styrene) (PS) and poly(vinyl acetate) (PVAc) on the other hand. Various functionalization reactions showed an overall efficient thiol‐ene process for conjugation reactions of polymers with low molecular weight compounds (∼90% coupling yield). However, while SEC and FT‐IR analysis of the conjugated PS‐PVAc products indicated qualitative evidence for a successful polymer–polymer conjugation, 1 H NMR and elemental analysis revealed a low conjugation efficiency of about 23% for a thiol‐to‐ene ratio equal to one. Blank reactions using typical thiol‐ene conditions indicated that bimolecular termination reactions occur as competitive side reactions explaining why a molecular weight increase is observed even though the thiol‐ene reaction was not successful. The extensive study of both research groups indicates that radical thiol‐ene chemistry should not be proposed as a straightforward conjugation tool for polymer–polymer conjugation reactions. Head‐to‐head coupling is a major reaction pathway, which interrupts the propagation cycle of the thiol‐ene process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1699–1713, 2010
Estimating the photodissociation quantum yield from PLP-SEC peak heights
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY00412E
Stabilizing self-assembled nano-objects using light-driven tetrazole chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1PY00032B
Abstract: Tetrazole-driven photochemistry is exploited for the stabilization of self-assembled morphologies via light-triggered nitrile imine carboxylic acid ligation (NICAL).
Probing the reaction kinetics of vinyl acetate free radical polymerization via living free radical polymerization (MADIX)
Publisher: Elsevier BV
Date: 02-2006
4D Printing at the Microscale
Publisher: Wiley
Date: 19-12-2019
Investigation of the influence of the architectures of poly(vinyl pyrrolidone) polymers made via the reversible addition–fragmentation chain transfer/macromolecular design via the interchange of xanth
Publisher: Wiley
Date: 20-06-2006
DOI: 10.1002/POLA.21518
Post‐Functionalization of Polymers via Orthogonal Ligation Chemistry
Publisher: Wiley
Date: 29-04-2013
Abstract: The establishment of advanced living/controlled polymerization protocols allows for engineering synthetic polymers in a precise fashion. Combining advanced living/controlled polymerization techniques with highly efficient coupling chemistries facilitates quantitative, modular, and orthogonal functionalization of synthetic polymer strands at their chain termini as well as side-chain functionalization. The review highlights the current status of selected post-functionalization techniques of polymers via orthogonal ligation chemistries, major characteristics of the specific transformation chemistry, as well as the characterization of the products.
Effect of an added base on (4-cyanopentanoic acid)-4-dithiobenzoate mediated RAFT polymerization in water
Publisher: Elsevier BV
Date: 02-2006
New methods of polymer synthesis
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY90007F
The Mechanism and Kinetics of the RAFT Process: Overview, Rates, Stabilities, Side Reactions, Product Spectrum and Outstanding Challenges
Publisher: Wiley
Date: 23-01-2008
Direct Mapping of RAFT Controlled Macromolecular Growth on Surfaces via Single Molecule Force Spectroscopy
Publisher: American Chemical Society (ACS)
Date: 30-03-2016
DOI: 10.1021/ACSMACROLETT.6B00106
Abstract: Single molecule force spectroscopy (SMFS) is employed to gain insight into reversible addition-fragmentation chain transfer (RAFT) polymerization processes with living characteristics on glass surfaces. Surface-initiated (SI)-RAFT was selected to grow poly(hydroxyethyl methacrylate) (PHEMA). After aminolysis of the RAFT chain termini, thiol moieties serve as anchoring points for the gold tip of an atomic force microscope. The results allow to directly monitor the macromolecular growth of the surface-initiated polymerization. The obtained SMFS-based molecular weight distribution data of the polymers present on the surface indicate that the RAFT chain extension proceeds linearly with time up to high conversions. The current study thus adds SMFS as a valuable tool for the investigation of SI-RAFT polymerizations.
The RAFT Process as a Kinetic Tool: Accessing Fundamental Parameters of Free Radical Polymerization
Publisher: Wiley
Date: 23-01-2008
Synthesis of comb polymers via grafting‐onto macromolecules bearing pendant diene groups via the hetero‐Diels‐Alder‐RAFT click concept
Publisher: Wiley
Date: 08-03-2010
DOI: 10.1002/POLA.23943
Abstract: Comb polymers were synthesized by the “grafting‐onto” method via a combination of Reversible Addition‐Fragmentation Chain Transfer (RAFT) polymerization and the hetero‐Diels‐Alder (HDA) cycloaddition. The HDA reactive monomer trans, trans‐hexa‐2,4‐dienylacrylate (ttHA) was copolymerized with styrene via the RAFT process. Crosslinking was minimized by decreasing the monomer concentration—whilst keeping monomer to polymer conversions low—resulting in reactive backbones with on average one reactive pendant diene groups for 10 styrene units. The HDA cycloaddition was performed between the diene functions of the copolymer and a poly( n ‐butyl acrylate) (P n BA) prepared via RAFT polymerization with pyridin‐2‐yldithioformate, which can act as a dienophile. The coupling reactions were performed within 24 h at 50 °C and the grafting yield varies from 75% to 100%, depending on the number average molecular weight of the P n BA (3500 g mol −1 M n 13,000 g mol −1 ) grafted chain and the reaction stoichiometry. The molecular weights of the grafted block copolymers range from 19,000 g mol −1 to 58,000 g mol −1 with polydispersities close to 1.25. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1773–1781, 2010
Solvent Effects on Acrylate k(p) in Organic Media?-A Systematic PLP-SEC Study
Publisher: Wiley
Date: 31-10-2014
Abstract: The Arrhenius parameters of the propagation rate coefficient, kp , are determined employing high-frequency pulsed laser polymerization-size exclusion chromatography (PLP-SEC) for the homologous series of five linear alkyl acrylates (i.e., methyl acrylate (MA), butyl acrylate (BA), dodecyl acrylate (DA), stearyl acrylate (SA), and behenyl acrylate (BeA)) in 1 m solution in butyl acetate (BuAc) as well as in toluene. The comparison of the obtained kp values with the literature known values for bulk demonstrates that no significant solvent influence neither in BuAc nor in toluene on the propagation reaction compared to bulk is detectable. Concomitantly, the kp values in toluene and in BuAc solution display a similar increase with increasing number of C-atoms in the ester side chain as was previously reported for the bulk systems. These findings are in clear contrast to earlier studies, which report a decrease of kp with increasing ester side chain length in toluene. The additional investigation of the longest and shortest ester side chain acrylate (i.e., BeA and MA) over the entire experimentally available concentration range at one temperature (i.e., 50 °C) does not reveal any general concentration dependence and all observed differences in the kp are within the experimental error.
Fast and catalyst-free hetero-Diels–Alder chemistry for on demand cyclable bonding/debonding materials
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3PY00476G
The Influence of a Potential Diffusion Control on the Outcome of Modular Polymer–Polymer Click Conjugations
Publisher: Wiley
Date: 08-2011
High molecular weight acrylonitrile–butadiene architectures via a combination of RAFT polymerization and orthogonal copper mediated azide–alkyne cycloaddition
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY00547F
Dendrimers as scaffolds for multifunctional reversible addition–fragmentation chain transfer agents: Syntheses and polymerization
Publisher: Wiley
Date: 13-10-2004
DOI: 10.1002/POLA.20434
Poly(ethylene glycol) as a 'green solvent' for the RAFT polymerization of methyl methacrylate
Publisher: Elsevier BV
Date: 08-2010
A Supramolecular Approach to Macromolecular Self&;#x02010;Assembly: Cyclodextrin Host/Guest Complexes
Publisher: John Wiley &;#38; Sons, Inc.
Date: 11-08-2016
Photo-Induced Macromolecular Functionalization of Cellulose via Nitroxide Spin Trapping
Publisher: American Chemical Society (ACS)
Date: 26-04-2012
DOI: 10.1021/BM3001364
Light-fueled dynamic covalent crosslinking of single polymer chains in non-equilibrium states
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0SC05818A
Abstract: Synthetic polymers consume green light as fuel for intramolecular crosslinking, yielding non-equilibrium single chain nanoparticles that can be light-stabilised, kinetically and chemically trapped, or else unfold in the absence of light fuel.
Stability of star-shaped RAFT polystyrenes under mechanical and thermal stress
Publisher: Royal Society of Chemistry (RSC)
Date: 08-05-2014
DOI: 10.1039/C4PY00484A
Sunlight-induced crosslinking of 1,2-polybutadienes: access to fluorescent polymer networks
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3PY01381B
Efficient Photochemical Approaches for Spatially Resolved Surface Functionalization
Publisher: Wiley
Date: 09-2015
Abstract: Materials interfaces—with a gas, a liquid, or another solid—are highly important for advanced applications. Besides their topological design, controlling interactions at these interfaces is typically realized by tuning the chemical composition of the materials surface. In areas such as nanoscience or biology, it is, however, highly desirable to impart heterogeneously distributed properties. Photopatterning, more than micro‐ and nanoprinting methods, is often the method of choice for precise functionalization, especially in terms of versatility. Recently, a range of new or rediscovered photochemistry approaches have been applied to precision surface functionalization, with the common aim of increasing efficiency and resolution while concomitantly lowering the amount of required energy. A survey of such methods is presented in this Review, with a focus on those we have explored.
A Simple Approach to Micro-Patterned Surfaces by Breath Figures with Internal Structure Using Thermoresponsive Amphiphilic Block Copolymers
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/CH05186
Abstract: Employing hiphilic block copolymers in a casting process to obtain honeycomb-structured films via breath figures leads to a suborder of these porous films. A thermoresponsive block copolymer, polystyrene-block-poly(N-isopropyl acrylamide), was synthesized and used to test the arrangement of both blocks within the honeycomb-structured films. Contact angle measurements reveal that the surface of these films has a different composition compared to the structure of the pores. The pores were found to be enriched in hydrophilic sequences showing stimuli-responsive behavior, whereas the surface reacts like a typical hydrophobic porous film.
Honeycomb-structured porous films from polypyrrole-containing block copolymers prepared via RAFT polymerization as a scaffold for cell growth
Publisher: American Chemical Society (ACS)
Date: 25-03-2006
DOI: 10.1021/BM050858M
Abstract: Honeycomb-structured porous films were prepared using customized hiphilic block copolymers, synthesized by RAFT polymerization. Pyrrole was templated along an hiphilic block copolymer, composed of polystyrene and poly(acrylic acid). Subsequent oxidation of pyrrol to polypyrrole, resulted in the formation of a soluble polypyrrole-containing polymer. Gel permeation chromatography and dynamic light scattering studies confirmed the solubility of the resulting customized hiphilic block copolymer, in both water and organic solvent, forming either micelles or inverse aggregates. Porous films with a hexagonal array of micron-sized pores were generated with the polymer, using the breath figures templating technique. The resulting films were found to be non-cytotoxic and hence suitable as scaffolds for tissue engineering. Initial fibroblast cell culture studies on these scaffolds demonstrated a dependency of cell attachment on the pore size of scaffolds.
Light-Induced Step-Growth Polymerization of AB-Type Photo-Monomers at Ambient Temperature
Publisher: American Chemical Society (ACS)
Date: 30-01-2018
DOI: 10.1021/ACSMACROLETT.7B01001
Abstract: We introduce two AB-type monomers able to undergo a facile catalyst-free photoinduced polycycloaddition of photocaged dienes, enabling rapid Diels-Alder ligations under UV-irradiation (λ
Radical Polymerization: Reversing the Irreversible?
Publisher: Wiley
Date: 17-11-2009
Rapid Thiol‐Yne‐Mediated Fabrication and Dual Postfunctionalization of Micro‐Resolved 3D Mesostructures
Publisher: Wiley
Date: 15-05-2015
Quantifying Solvent Effects on Polymer Surface Grafting
Publisher: American Chemical Society (ACS)
Date: 18-06-2019
DOI: 10.1021/ACSMACROLETT.9B00336
Abstract: When grafting polymers onto surfaces, the reaction conditions critically influence the resulting interface properties, including the grafting density and molar mass distribution (MMD) on the surface. Herein, we show theoretically and experimentally that the application of poor solvents is beneficial for the "grafting-to" approach. We demonstrate the effect by grafting poly(methyl methacrylate) chains on silica nanoparticles in different solvents and compare the MMD of the polymer in solution before and after grafting via size exclusion chromatography (SEC). The shorter polymer chains are preferentially grafted onto the surface, leading to a distortion effect between the MMD in solution and on surfaces. The molecular weight distortion effect is significantly higher for ethyl acetate (good solvent quality, difference in
Tacticity dependence of single chain polymer folding
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY00133C
Abstract: Precision polymerization techniques offer the exciting opportunity to manufacture single-chain nanoparticles (SCNPs) with intramolecular crosslinks placed in specific positions along the polymer chain.
Untapped potential for debonding on demand: the wonderful world of azo-compounds
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7MH00920H
Abstract: We highlight and explore recent advances in the design of debonding on demand soft matter materials based on the azo-motif.
Guiding Cell Attachment in 3D Microscaffolds Selectively Functionalized with Two Distinct Adhesion Proteins
Publisher: Wiley
Date: 24-11-2016
Abstract: The combination of three different photoresists into a single direct laser written 3D microscaffold permits functionalization with two bioactive full-length proteins. The cell-instructive microscaffolds consist of a passivating framework equipped with light activatable constituents featuring distinct protein-binding properties. This allows directed cell attachment of epithelial or fibroblast cells in 3D.
A Guanidine-Based Superbase as Efficient Chemiluminescence Booster
Publisher: Springer Science and Business Media LLC
Date: 10-10-2019
DOI: 10.1038/S41598-019-51105-Z
Abstract: We introduce the guanidine-based superbase 1,5,7-triaza-bicyclo-[4.4.0]dec-5-ene (TBD) as efficient enabler for chemiluminescence (CL) based on luminol in a simple, ready-to-use two component system. The strong CL is generated by the superbase’s properties as peroxidase mimetic and bifunctional coreactant. The herein established concept allows for CL enabling molecules (superbases) to be readily implemented in larger molecular structures, including in polymers.
Spatially resolved photochemical coding of reversibly anchored cysteine-rich domains
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TB00962C
Abstract: We present a novel methodology to create rewritable surfaces using cysteine-rich domains via a combination of photolithography and reversible peptide-driven disulfide formation.
Two Sides of the Same Coin: Light as a Tool to Control and Map Microsphere Design
Publisher: American Chemical Society (ACS)
Date: 23-06-2021
DOI: 10.1021/ACSMACROLETT.1C00319
Abstract: Herein, we establish the effect of intensity and wavelength on the size of microparticles formed via precipitation polymerization, employing photocrosslinkable prepolymers. Simultaneous measurement of backscattered laser irradiation enabled real-time tracking of particle growth and provides the ability to vary the LED intensity (λ
Cyclodextrin-Complexed RAFT Agents for the Ambient Temperature Aqueous Living/Controlled Radical Polymerization of Acrylamido Monomers
Publisher: American Chemical Society (ACS)
Date: 25-08-2011
DOI: 10.1021/MA2011969
A Mild and Efficient Approach to Functional Single-Chain Polymeric Nanoparticles via Photoinduced Diels–Alder Ligation
Publisher: American Chemical Society (ACS)
Date: 11-10-2013
DOI: 10.1021/MA4015033
Reversible Surface Engineering via Nitrone-Mediated Radical Coupling
Publisher: American Chemical Society (ACS)
Date: 19-02-2018
DOI: 10.1021/ACS.LANGMUIR.7B03167
Abstract: Efficient and simple polymer conjugation reactions are critical for introducing functionalities on surfaces. For polymer surface grafting, postpolymerization modifications are often required, which can impose a significant synthetic hurdle. Here, we report two strategies that allow for reversible surface engineering via nitrone-mediated radical coupling (NMRC). Macroradicals stemming from the activation of polymers generated by copper-mediated radical polymerization are grafted via radical trapping with a surface-immobilized nitrone or a solution-borne nitrone. Since the product of NMRC coupling features an alkoxyamine linker, the grafting reactions can be reversed or chain insertions can be performed via nitroxide-mediated polymerization (NMP). Poly( n-butyl acrylate) ( M
Mass spectrometry in polymer chemistry: a state-of-the-art up-date
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B9PY00347A
The long and the short of polymer grafting
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8PY01470A
Abstract: Polymer chains are grafted depending on their size onto solid interfaces, leading to a distortion of the surface grafted size distribution. We herein predict and quanitify this distortion effect, which has critical consequences for functional polymer interface design.
Functional Materials Research at Queensland University of Technology's Centre for Materials Science
Publisher: Wiley
Date: 04-2022
Investigating the propagation kinetics of a novel class of nitrogen-containing methacrylates via PLP-SEC
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6PY00867D
Abstract: The Mark–Houwink–Kuhn–Sakurada parameters as well as Arrhenius parameters of the propagation rate coefficient for a new group of nitrogen-containing methacrylates were determined via triple detector SEC and pulsed laser polymerization–size exclusion chromatography, respectively.
Highly efficient photoluminescent Cu(i)–PyrPHOS-metallopolymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3TC32347A
Acid‐Degradable Core‐Crosslinked Micelles Prepared from Thermosensitive Glycopolymers Synthesized via RAFT Polymerization
Publisher: Wiley
Date: 11-01-2008
Modeling the reversible addition-fragmentation chain transfer process in cumyl dithiobenzoate-mediated styrene homopolymerizations: Assessing rate coefficients for the addition-fragmentation equilibrium
Publisher: Wiley
Date: 14-03-2001
DOI: 10.1002/POLA.1112
Green light enabled Staudinger–Bertozzi ligation
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CC00911K
Abstract: A photochemical approach towards green light-enabled Staudinger–Bertozzi ligation, and its application in polymer endgroup modification and surface patterning.
Understanding Reactivity Patterns in Light‐Induced Nitrile Imine Mediated Tetrazole–Ene Cycloadditions
Publisher: Wiley
Date: 25-01-2017
State‐of‐the‐Art Analytical Methods for Assessing Dynamic Bonding Soft Matter Materials
Publisher: Wiley
Date: 30-04-2014
Abstract: Dynamic bonding materials are of high interest in a variety of fields in material science. The reversible nature of certain reaction classes is frequently employed for introducing key material properties such as the capability to self-heal. In addition to the synthetic effort required for designing such materials, their analysis is a highly complex--yet important--endeavor. Herein, we critically review the current state of the art analytical methods and their application in the context of reversible bonding on demand soft matter material characterization for an in-depth performance assessment. The main analytical focus lies on the characterization at the molecular level.
Degradation of Poly(methyl methacrylate) Model Compounds Under Extreme Environmental Conditions
Publisher: Wiley
Date: 30-06-2010
Design of broadband SERS substrates by the laser-induced aggregation of gold nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TC04286K
Abstract: Direct laser writing has been used to produce substrates for multi-wavelength SERS analysis.
Determination of Propagation Rate Coefficients for Methyl and 2-Ethylhexyl Acrylate via High Frequency PLP−SEC under Consideration of the Impact of Chain Branching
Publisher: American Chemical Society (ACS)
Date: 07-12-2010
DOI: 10.1021/MA102130H
The Long and the Short of Radical Polymerization
Publisher: American Chemical Society (ACS)
Date: 27-01-2015
DOI: 10.1021/MA5017659
Synthesis of Star Polymers using RAFT Polymerization: What is Possible?
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/CH06297
Abstract: Various pathways to generate star polymers using reversible addition–fragmentation transfer (RAFT) are discussed. Similar to other polymerization techniques, star polymers can be generated using arm-first and core-first approaches. Unique to the RAFT process is the sub ision of the core-first approach into the R-group and Z-group approaches, depending on the attachment of the RAFT agent to the multifunctional core. The mechanism of the R- and Z-group approaches are discussed in detail and it is shown that both techniques have to overcome difficulties arising from termination reactions. Termination reactions were found to broaden the molecular weight. However, these side reactions can be limited by careful design of the synthesis. Considerations include RAFT and radical concentration, number of arms, type of RAFT agent and monomer. Despite obvious challenges, the RAFT process is highly versatile, allowing the synthesis of novel polymer architectures such as poly(vinyl acetate) and poly(vinyl pyrrolidone) star polymers.
Bis-Hydrophilic Block Terpolymers via RAFT Polymerization: Toward Dynamic Micelles with Tunable Corona Properties
Publisher: American Chemical Society (ACS)
Date: 31-10-2008
DOI: 10.1021/MA801215Q
Reversible addition fragmentation chain transfer copolymerization: influence of the RAFT process on the copolymer composition
Publisher: Elsevier BV
Date: 05-2004
A Perfect Couple: PLP/SEC/ESI‐MS for the Accurate Determination of Propagation Rate Coefficients in Free Radical Polymerization
Publisher: Wiley
Date: 23-12-2009
Rapid Bonding/Debonding on Demand: Reversibly Cross-Linked Functional Polymers via Diels−Alder Chemistry
Publisher: American Chemical Society (ACS)
Date: 10-06-2010
DOI: 10.1021/MA100945B
Ultra-Fast RAFT-HDA Click Conjugation: An Efficient Route to High Molecular Weight Block Copolymers
Publisher: Wiley
Date: 28-10-2009
Abstract: The use of the reversible addition fragmentation chain transfer-hetero Diels-Alder (RAFT-HDA) click reaction for the modular construction of block copolymers is extended to the generation of high molecular weight materials. Cyclopentadienyl end-functionalized polystyrene (PS-Cp) prepared via both atom transfer radical polymerization (ATRP) and the RAFT process are conjugated to poly(isobornyl acrylate) (PiBoA) (also prepared via RAFT polymerization) to achieve well-defined block copolymers with molecular weights ranging from 34 000 to over 100 000 g · mol(-1) and with small polydispersities (PDI < 1.2). The conjugation reactions proceeded in a very rapid fashion (less than 10 min in the majority of cases) under ambient conditions of temperature and atmosphere. The present study demonstrates-for the first time-that RAFT-HDA click chemistry can provide access to high molecular weight block copolymers in a simple and straight-forward fashion.
ATRP poly(acrylate) star formation: A comparative study between MALDI and ESI mass spectrometry
Publisher: Elsevier BV
Date: 04-2009
Bis(mesitoyl)phosphinic acid: photo-triggered release of metaphosphorous acid in solution
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC05219C
Abstract: We report a photo-triggered, two-step fragmentation mechanism generating metaphosphorous acid.
Hetero‐Diels‐Alder‐Cycloaddition mit RAFT‐Polymeren als Biokonjugationsplattform
Publisher: Wiley
Date: 02-09-2020
Correction: Chemical approaches to synthetic polymer surface biofunctionalization for targeted cell adhesion using small binding motifs
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5SM90037A
Visible-light-induced click chemistry
Publisher: Wiley
Date: 15-07-2015
Abstract: A rapid and catalyst-free cycloaddition system for visible-light-induced click chemistry is reported. A readily accessible photoreactive 2H-azirine moiety was designed to absorb light at wavelengths above 400 nm. Irradiation with low-energy light sources thus enables efficient small-molecule synthesis with a erse range of multiple-bond-containing compounds. Moreover, in order to demonstrate the efficiency of the current approach, quantitative ligation of the photoactivatable chromophore with functional polymeric substrates was performed and full conversion with irradiation times of only 1 min at ambient conditions was achieved. The current report thus presents a highly efficient method for applications involving selective cycloaddition to electron-deficient multiple-bond-containing materials.
Chain-length dependence of free-radical termination rate deduced from laser single-pulse experiments
Publisher: Wiley
Date: 11-2000
DOI: 10.1002/1521-3919(20001101)9:8<442::AID-MATS442>3.0.CO;2-I
Photoclickable Surfaces for Profluorescent Covalent Polymer Coatings
Publisher: Wiley
Date: 17-11-2011
Determination of the propagation rate coefficient of acrylonitrile
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0PY00019A
Abstract: For the first time, accurate propagation rate coefficients for acrylonitrile are determined via the pulsed laser polymerization–size exclusion chromatography technique.
50th Anniversary Perspective: Polymer Functionalization
Publisher: American Chemical Society (ACS)
Date: 26-06-2017
Lichtinduzierte orthogonale Bildung kovalenter Bindungen durch zwei Wellenlängen
Publisher: Wiley
Date: 24-04-2019
Ultrarapid Approaches to Mild Macromolecular Conjugation
Publisher: Wiley
Date: 27-04-2011
Thioketone‐Mediated Polymerization with Dithiobenzoates: Proof for the Existence of Stable Radical Intermediates in RAFT Polymerization
Publisher: Wiley
Date: 03-05-2012
Abstract: A novel dithioester control agent [dimethyltetrathioterephtalate (DMTTT)] is presented for the thioketone-mediated radical polymerization (TKMP) of n-butyl acrylate. The rate of polymerization is significantly decreased in the presence of DMTTT indicating formation of dormant radical species. During polymerization, molar masses increase linearly with monomer conversion with reasonably narrow initial molar mass distributions (PDI between 1.3 and 1.8), whereas the dispersity increases during the course of the polymerization due to irreversible termination of both propagating and dormant radicals. The present results thus highlight the possibility of a mixed mechanism operating in RAFT polymerization, which combines slow fragmentation (long-lived intermediates) and intermediate radical termination.
Amphiphilic block copolymers based on cyclodextrin host–guest complexes via RAFT-polymerization in aqueous solution
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B818897A
Abstract: We present-for the first time-the synthesis of hiphilic block copolymers via RAFT polymerization of a randomly methylated beta-CD-complexed hydrophobic acrylamide and hydrophilic N,N'-dimethylacrylamide from homogeneous aqueous solution.
Multi-material 3D microstructures with photochemically adaptive mechanical properties
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TC02751K
Abstract: Multi-material 3D microstructures with photochemically adaptive mechanical properties are fabricated and we explore how their photo-responsiveness is related to the parameters that are used during their creation via 3D laser lithography.
Synthesis of a Macromonomer Library from High‐Temperature Acrylate Polymerization
Publisher: Wiley
Date: 12-2009
Abstract: The auto-initiated high temperature acrylate polymerization represents a versatile route for the synthesis of macromonomer building blocks. Various macromonomers were synthesized via this route based on methyl, ethyl, n-butyl, t-butyl, 2-ethylhexyl, isobornyl and 2-[[(butylamino)carbonyl]oxy]ethyl acrylate. The synthesis requires a temperature of 140 °C and is carried out in a 5 wt.-% solution of hexyl acetate. The macromonomer library is fully characterized via electrospray ionization mass spectrometry (ESI-MS). The amount of macromonomers containing the geminal double bond lies in between 82 and 95%, depending on the monomer type. The achievable molecular weight of the macromonomers is located between 800 and 2 000 g·mol(-1) with a polydispersity of close to 1.6. In addition, it is demonstrated that radical initiators are useful add-ons (to circumvent the inhibition time observed during initiator-free synthesis) without interfering in the actual polymerization as no initiator-fragment containing products are identified via high resolution mass spectrometry.
Visible‐Light‐Induced Control over Reversible Single‐Chain Nanoparticle Folding
Publisher: Wiley
Date: 04-08-2023
Abstract: We introduce a class of single‐chain nanoparticles (SCNPs) that respond to visible light ( λ max =415 nm) with complete unfolding from their compact structure into linear chain analogues. The initial folding is achieved by a simple esterification reaction of the polymer backbone constituted of acrylic acid and polyethylene glycol carrying monomer units, introducing bimane moieties, which allow for the photochemical unfolding, reversing the ester‐bond formation. The compaction and the light driven unfolding proceed cleanly and are readily followed by size exclusion chromatography (SEC) and diffusion ordered NMR spectroscopy (DOSY), monitoring the change in the hydrodynamic radius ( R H ). Importantly, the folding reaction and the light‐induced unfolding are reversible, supported by the high conversion of the photo cleavage. As the unfolding reaction occurs in aqueous systems, the system holds promise for controlling the unfolding of SCNPs in biological environments.
Kooperative Netzwerkbildung mittels zweifarben Aktivierung von λ‐orthogonalen Chromophoren
Publisher: Wiley
Date: 24-07-2023
Abstract: Die unabhängige Aktivierung von lichtreaktiven Funktionalitäten innerhalb eines Moleküls stellt eine besondere Herausforderung dar. Wir nutzen die Kombination von zwei sequenzunabhängigen λ‐orthogonalen Chromophoren innerhalb eines heterotelechelen Quervernetzer‐Moleküls und ihre gegenläufigen Reaktivitäten mit demselben Reaktionspartner, einem Copolymer mit Maleimid‐Seitengruppen, um Netzwerkbildung exklusiv durch die Bestrahlung mit zwei Lichtfarben zu induzieren. Bestrahlunge mit nur einer der beiden Lichtfarben führt zur einseitigen Reaktion des Quervernetzers und somit zur Postfunktionalisierung des Polymers. Die Netzwerkbildung hingegen wird ausschließlich durch sequenzielle oder simultane zweifarben Bestrahlung erzielt. Dieses lichtreaktive System zeigt exemplarisch den Nutzen von Wellenlängen‐orthogonaler Chemie in der makromolekularen Synthese.
More than Expected: Overall Initiation Efficiencies of Mono-, Bis-, and Tetraacylgermane Radical Initiators
Publisher: American Chemical Society (ACS)
Date: 21-12-2018
Complex macromolecular architecture design via cyclodextrin host/guest complexes
Publisher: Elsevier BV
Date: 2014
Efficient and mild modification of Si surfaces via orthogonal hetero Diels‐Alder chemistry
Publisher: Wiley
Date: 06-11-2009
DOI: 10.1002/POLA.23756
RAFT-based Polystyrene and Polyacrylate Melts under Thermal and Mechanical Stress
Publisher: American Chemical Society (ACS)
Date: 07-10-2013
DOI: 10.1021/MA401749H
Wellenlängengesteuerte photochemische Synthese von Phenalendiimiden
Publisher: Wiley
Date: 18-03-2021
Formation of honeycomb‐structured, porous films via breath figures with different polymer architectures
Publisher: Wiley
Date: 02-03-2006
DOI: 10.1002/POLA.21334
“Clicking” Polymers or Just Efficient Linking: What Is the Difference?
Publisher: Wiley
Date: 03-12-2010
International Biannual Belgian Polymer Group Award: C. Barner‐Kowollik / Election to the Bavarian Academy of Science and Humanities: H.‐U. Reissig / Civic Medal First Class and Honorary Doctorate: G.
Publisher: Wiley
Date: 04-10-2012
Facile Preparation of Supramolecular H-Shaped (Ter)polymers via Multiple Hydrogen Bonding
Publisher: American Chemical Society (ACS)
Date: 22-02-2013
DOI: 10.1021/MZ400066R
Abstract: A well-defined Hamilton wedge (HW) midchain functionalized block copolymer, i.e., polyethylene glycol-
Suppressing Pseudomonas aeruginosa adhesion via non-fouling polymer brushes
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA12663G
Abstract: In the current study, well-defined polymer brushes are shown as an effective surface modification to resist biofilm formation from opportunistic pathogens.
Self‐directed formation of uniform unsaturated macromolecules from acrylate monomers at high temperatures
Publisher: Wiley
Date: 18-04-2008
DOI: 10.1002/POLA.22676
Has Click Chemistry Lead to a Paradigm Shift in Polymer Material Design?
Publisher: Wiley
Date: 17-06-2009
Grafting Efficiency of Synthetic Polymers onto Biomaterials: A Comparative Study of Grafting-from versus Grafting-to
Publisher: American Chemical Society (ACS)
Date: 24-10-2012
DOI: 10.1021/BM3013132
Abstract: In the present study, the two grafting techniques grafting-from - by activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) - and grafting-to - by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) - were systematically compared, employing cellulose as a substrate. In order to obtain a meaningful comparison, it is crucial that the graft lengths of the polymers that are grafted from and to the substrates are essentially identical. Herein, this was achieved by utilizing the free polymer formed in parallel to the grafting-from reaction as the polymer for the grafting-to reaction. Four graft lengths were investigated, and the molar masses of the four free polymers (21 ≤ M(n) ≤ 100 kDa 1.07 ≤ Đ(M) ≤ 1.26), i.e. the polymers subsequently employed in the grafting-to reaction, were shown to be in the same range as the molar masses of the polymers grafted from the surface (23 ≤ M(n) ≤ 87 kDa 1.08 ≤ Đ(M) ≤ 1.31). The molecular weights of the chains grafted from the surface were established after cleavage from the cellulose substrates via size exclusion chromatography (SEC). High-resolution Fourier transform infrared microscopy (FT-IRM) was employed as an efficient tool to study the spatial distribution of the polymer content on the grafted substrates. In addition, the functionalized substrates were analyzed by X-ray photoelectron spectroscopy (XPS), contact angle (CA) measurements, and field-emission scanning electron microscopy (FE-SEM). For cellulose substrates modified via the grafting-from approach, the content of polymer on the surfaces increased with increasing graft length, confirming the possibility to tailor not only the length of the polymer grafts but also the polymeric content on the surface. In comparison, for the grafting-to reaction, the grafted content could not be controlled by varying the length of the preformed polymer: the polymer content was essentially the same for the four graft lengths. Consequently, the obtained results, when employing cellulose as a substrate and under these conditions, suggest that the grafting-from approach is superior to the grafting-to technique with respect to controlling the distribution of the polymeric content on the surface.
Mechanism and kinetics of dithiobenzoate‐mediated RAFT polymerization. I. The current situation
Publisher: Wiley
Date: 11-09-2006
DOI: 10.1002/POLA.21589
Modeling the Effects of Reactor Backmixing on RAFT Polymerization
Publisher: Wiley
Date: 04-10-2010
Quantifying the eficiency of photoinitiation processes in methyl methacrylate free radical polymerization via electrospray ionization mass spectrometry
Publisher: American Chemical Society (ACS)
Date: 17-02-2009
DOI: 10.1021/MA802308Z
Poly(vinyl ester) Star Polymers via Xanthate-Mediated Living Radical Polymerization: From Poly(vinyl alcohol) to Glycopolymer Stars
Publisher: American Chemical Society (ACS)
Date: 27-05-2005
DOI: 10.1021/MA050050U
Two Functions from a Single Photoresist: Tuning Microstructure Degradability from Light‐Stabilized Dynamic Materials
Publisher: Wiley
Date: 29-03-2023
Abstract: A photoresist—based on a light‐stabilized dynamic material driven by an out‐of‐equilibrium photo‐Diels–Alder reaction of triazolinediones with naphthalenes—whose ability to intrinsically degrade postprinting can be tuned by a simple adjustment of laser intensity during 3D laser lithography is introduced. The resist's ability to form stable networks under green light irradiation that degrade in the dark is transformed into a tunable degradable 3D printing material platform. In‐depth characterization of the printed microstructures via atomic force microscopy before and during degradation reveals the high dependency of the final structures’ properties on the writing parameters. Upon identifying the ideal writing parameters and their effect on the network structure, it is possible to selectively toggle between stable and fully degradable structures. This simplifies the direct laser writing manufacturing process of multifunctional materials significantly, which typically requires the use of separate resists and consecutive writing efforts to achieve degradable and nondegradable material sections.
Reporting pH-sensitive drug release via unpaired spin fluorescence silencing
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7PY01942D
Abstract: We pioneer an approach for the visualization of a self-reporting pH-controlled molecular release of a fluorescent drug from a nitroxide polymer scaffold.
On the Quantitative Click Conjugation of Molecular Weight Distributions: What Can Theoretically Be Expected?
Publisher: Wiley
Date: 22-09-2009
Abstract: The assessment of the success of a click conjugation for block copolymer formation often occurs via ill-defined criteria based on the qualitative shape of the size exclusion chromatography (SEC) distribution as well as unsuitable characteristics of these molecular weight distribution such as the peak molecular weight, M(p) . The data presented herein illustrate that from the shape of the SEC distribution, w(log M) versus log M, of the click product-under the assumption of a 100% efficient conjugation reaction-a conclusion about the effectiveness of the click conjugation cannot be derived. It is demonstrated that under certain conditions multi-modal molecular weight distributions are obtained from two well-defined monomodal initial distributions. Similarly, the comparison of peak maxima between the conjugate and the initial SEC distributions is a poorly defined criterion to assess the success of a conjugation. The only reliable assessment for the success of the click coupling reaction is the true number average molecular weight, $\\overline M _{\\rm n}$, of the SEC distribution of the click product, as well as a plot of the concentration or number distributions, c versus M, of the precursors and product polymer.
Reversible addition - Fragmentation chain transfer polymerization initiated with ultraviolet radiation
Publisher: American Chemical Society (ACS)
Date: 27-08-2002
DOI: 10.1021/MA0204296
Control of methyl methacrylate radical polymerization via Enhanced Spin Capturing Polymerization (ESCP)
Publisher: Elsevier BV
Date: 08-2010
Controlling the shape of 3D microstructures by temperature and light
Publisher: Springer Science and Business Media LLC
Date: 16-01-2019
DOI: 10.1038/S41467-018-08175-W
Abstract: Stimuli-responsive microstructures are critical to create adaptable systems in soft robotics and biosciences. For such applications, the materials must be compatible with aqueous environments and enable the manufacturing of three-dimensional structures. Poly( N -isopropylacrylamide) (pNIPAM) is a well-established polymer, exhibiting a substantial response to changes in temperature close to its lower critical solution temperature. To create complex actuation patterns, materials that react differently with respect to a stimulus are required. Here, we introduce functional three-dimensional hetero-microstructures based on pNIPAM. By variation of the local exposure dose in three-dimensional laser lithography, we demonstrate that the material parameters can be altered on demand in a single resist formulation. We explore this concept for sophisticated three-dimensional architectures with large- litude and complex responses. The experimental results are consistent with numerical calculations, able to predict the actuation response. Furthermore, a spatially controlled response is achieved by inducing a local temperature increase by two-photon absorption of focused light.
Zweifarbiges Licht in der Durchflusssynthese für makromolekulares Design
Publisher: Wiley
Date: 08-06-2020
Abstract: Wir beschreiben den Aufbau eines photochemischen Durchflussreaktors für λ‐orthogonale Reaktionen in sequenzieller Bestrahlung mit zwei unterschiedlichen Lichtfarben (λ 1 =350 nm und λ 2 =410 nm). Entscheidend hierbei ist, dass beide photochemisch reaktive Gruppen (ein Chalkon, das im sichtbaren Licht reagiert und ein UV‐aktivertes Dien) in der Reaktionslösung vorliegen. Wir zeigen das Vermögen der Durchflusssynthese mit zweierlei farbigem Licht durch wellenlängenselektive Endgruppenmodifikation und anschließenden Ringschluss des Polymers mittels [2+2]‐Cycloaddition. Wir zeigen zudem, dass der höher‐energetische Wellenlängenbereich keine Reaktion des Chalkons auslöst, was das wahre λ‐orthogonale Wesen der Photo‐Durchflusssynthese belegt. Die Studie eröffnet erstmalig das Gebiet der Photo‐Durchflussreaktionen für λ‐orthogonale Photochemie.
Global Trends for kp? The Influence of Ester Side Chain Topography in Alkyl (Meth)Acrylates − Completing the Data Base
Publisher: American Chemical Society (ACS)
Date: 05-05-2014
DOI: 10.1021/MA500304F
Preparation of Reactive Three‐Dimensional Microstructures via Direct Laser Writing and Thiol‐ene Chemistry
Publisher: Wiley
Date: 23-01-2013
Abstract: Three-dimensional microstructures are fabricated employing the direct laser writing process and radical thiol-ene polymerization. The resin system consists of a two-photon photoinitiator and multifunctional thiols and olefins. Woodpile photonic crystals with 22 layers and a rod distance of 2 μm are fabricated. The structures are characterized via scanning electron microscopy and focused ion beam milling. The thiol-ene polymerization during fabrication is verified via infrared spectroscopy. The structures are grafted in a subsequent thiol-Michael addition reaction with different functional maleimides. The success of the grafting reaction is evaluated via laser scanning microscopy and X-ray photoelectron spectroscopy. The grafting density is calculated to be close to 200 molecules μm(-2) .
Ambient temperature catalyst-free light-induced preparation of macrocyclic aliphatic polyesters
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CC49067J
Abstract: The light induced, catalyst-free ambient temperature preparation of macrocyclic aliphatic polyesters is pioneered. Based on the photo-induced Diels-Alder reaction of orthoquinodimethane and acrylate moieties, cyclic polyesters of high purity are readily synthesized. Considering the high tolerance to functional groups and the orthogonality of the ligation, the reported protocol can be easily transferred to a large range of polymers, complex topologies (tadpole, sun-shaped, jellyfish, etc.) and applications.
The Power of Action Plots: Unveiling Reaction Selectivity of Light‐Stabilized Dynamic Covalent Chemistry
Publisher: Wiley
Date: 29-08-2023
Abstract: Exploiting the optimum wavelength of reactivity for efficient photochemical reactions has been well‐established based on the development of photochemical action plots. We herein demonstrate the power of such action plots by a remarkable ex le of the wavelength‐resolved photochemistry of two triazolinedione (TAD) substrates, i.e., aliphatic and aromatic substituted, that exhibit near identical absorption spectra yet possess vastly disparate photoreactivity. We present our findings in carefully recorded action plots, from which reaction selectivity is identified. The profound difference in photoreactivity is exploited by designing a ‘hybrid’ bisfunctional TAD molecule, enabling the formation of a dual‐gated reaction manifold that demonstrates the exceptional and site‐selective (photo)chemical behavior of both TAD substrates within a single small molecule.
Chapter 6. Recent Developments in Nitroxide Mediated Polymerization
Publisher: Royal Society of Chemistry
Date: 2015
Supramolecular X- and H-shaped star block copolymers via cyclodextrin-driven supramolecular self-assembly
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3PY01580G
On-demand acid-gated fluorescence switch-on in photo-generated nanospheres
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC01557A
Abstract: Polymer particles are synthesized using a photo-active ortho -methyl benzaldehyde with a terminal alkyne for cross-linking. The reactive 1,4-dihydronaphthalene at every cross-linking point undergoes aromatisation to a fluorescent naphthalene upon exposure to acid.
Biomimetic Dopamine‐Diels–Alder Switches
Publisher: Wiley
Date: 12-03-2013
Abstract: Mussel adhesives function as tools for surface modifications of a wide variety of materials due to their remarkable adhesion properties. Herein, a combination of bioinspired mussel adhesives based on a dopamine derivative, polymer chemistry, and well-established Diels-Alder (DA) chemistry leads to a bioinspired switchable surface system that possesses the capability of attaching and detaching specific polymers on demand. A dopaminemaleimide compound, which has been attached to a gold surface under maritime conditions undergoes DA- and retro-DA-click-conjugations with cyclopentadiene-carrying PEG chains. The surface attachment and the subsequent DA/rDA cycles are evidenced via XPS analysis.
Visible Light Activation of Spin‐Silenced Fluorescence
Publisher: Wiley
Date: 24-05-2018
Abstract: A self-reporting, profluorescent, visible light-induced release system is introduced. Fluorescence activation is enabled by a mild remote trigger signal that can be monitored with the naked-eye in real time. The light-responsive spin-silenced polymer is synthesized via an Ugi post-polymerization modification incorporating paramagnetic nitroxides and a light cleavable fluorophore moiety.
A Self‐Reporting Tetrazole‐Based Linker for the Biofunctionalization of Gold Nanorods
Publisher: Wiley
Date: 21-08-2015
Abstract: A photochemical approach based on nitrile imine-mediated tetrazole-ene cycloaddition is introduced to functionalize gold nanorods with biomolecules. For this purpose, a bifunctional, photoreactive linker containing thioctic acid as the Au anchoring group and a tetrazole moiety for the light-induced reaction with maleimide-capped DNA was prepared. The tetrazole-based reaction on the nanoparticles' surface results in a fluorescent pyrazoline product allowing for the spectroscopic monitoring of the reaction. This first ex le of nitrile imine-mediated tetrazole-ene cycloaddition (NITEC)-mediated biofunctionalization of Au nanorods paves the way for the attachment of sensitive biomolecules, such as antibodies and other proteins, under mild conditions and expands the toolbox for the tailoring of nanomaterials.
Light induced polyethylene ligation
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY00717A
Abstract: We introduce a photoreactive polyethylene (PE) derivative, which upon light irradiation ( λ max = 365 nm) can effectively react to form well-defined block copolymers with polystyrene and poly(methyl methacrylate).
Ambient temperature RAFT polymerization of acrylic acid initiated with ultraviolet radiation in aqueous solution
Publisher: American Chemical Society (ACS)
Date: 03-04-2007
DOI: 10.1021/MA0703094
High temperature synthesis of vinyl terminated polymers based on dendronized acrylates: a detailed product analysis study
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0PY00411A
Abstract: The article focuses on the combination of dendrons with high temperature acrylate polymerization for the generation of dendronized macromonomers.
Correlating In-Depth Mechanistic Understanding with Mechanical Properties of High-Temperature Resistant Cyclic Imide Copolymers
Publisher: American Chemical Society (ACS)
Date: 25-10-2018
Vibrant Macromolecular Science at the 30th Australasian Polymer Symposium
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CH09129
Outstanding Reviewers for Polymer Chemistry in 2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9PY90051A
Embedding multiple site-specific functionalities into polymer chains via nitrone-mediated radical coupling reactions
Publisher: Wiley
Date: 03-2017
DOI: 10.1002/POLA.24639
Abstract: A facile method to generate polymer materials with embedded functional groups at known and precise positions along the polymer backbone is described. In the presented approach, well‐defined bifunctional poly(isobornyl acrylate)s preformed via atom transfer radical polymerization (ATRP) containing α,ω‐bromo end groups are reactivated and subsequently coupled in a stepwise manner via the nitrone‐mediated radical coupling (NMRC) technique. The generated polymers contain on average four nitrone moieties at evenly spaced locations. The number of embedded functionalities, and thus, the size of the polymer is limited by disproportionation reactions occurring during the nitroxide termination sequence. Using the nitrone as a functional carrier, secondary functionalities can be incorporated into the polymer with ease. To exemplify such an approach, an alkyne‐functionalized nitrone is used to construct a multisegment structure via NMRC reactions followed by postmodification of the obtained polymers with 3‐mercaptopropionic acid via UV‐induced thiol‐yne reactions. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Dual-Gated Chain Shattering Based on Light Responsive Benzophenones and Thermally Responsive Diels–Alder Linkages
Publisher: American Chemical Society (ACS)
Date: 12-07-2017
Bestimmung der Verknüpfungspunkte in fluoreszenten Polymernetzwerken
Publisher: Wiley
Date: 14-04-2018
Vorbeugen oder Heilen – die beispiellose Notwendigkeit von selbstberichtenden Materialien
Publisher: Wiley
Date: 26-02-2021
Abstract: Selbstberichtende intelligente Materialien sind in der modernen Polymer‐Materialwissenschaft von großer Bedeutung, da sie die autonome Erkennung von Veränderungen in synthetischen Polymeren, Materialien oder Verbundstoffen ermöglichen. Obwohl diese Materialien wichtige Vorteile bieten, haben sie wesentlich weniger Aufmerksamkeit erhalten als selbstheilende Materialien. Die Rückmeldung über Systemveränderungen und deren genaue Position ist jedoch von größter Bedeutung, um eine Ausbreitung zu verhindern. Daher geben wir hier einen kritischen Überblick über die Chemie selbstberichtender weicher Materialien und zeigen auf, wie aktuelle Herausforderungen und Einschränkungen durch die Übertragung selbstberichtender Forschungskonzepte aus dem Labor in die Industrie überwunden werden können. Besonders im Bereich der diagnostischen selbstberichtenden Systeme weist die jüngste SARS‐CoV‐2‐Pandemie auf einen dringenden Bedarf an solchen Konzepten hin, welche die Anwesenheit von Viren oder Bakterien auf und in Materialien auf selbstberichtende Weise anzeigen.
UV-Triggered End Group Conversion of Photo-Initiated Poly(methyl methacrylate)
Publisher: American Chemical Society (ACS)
Date: 25-07-2012
DOI: 10.1021/MA301275B
Dynamic Nitroxide Functional Materials.
Publisher: Wiley
Date: 16-11-2018
Abstract: A substrate-independent and versatile coating platform for (spatially resolved) surface functionalization, based on nitroxide radical coupling (NRC) reactions and the formation of thermo-labile alkoxyamine functional groups, was introduced. Nitroxide-decorated poly(glycidyl methacrylate) (PGMA) microspheres, obtained through bioinspired copolymer surface deposition using dopamine and a nitroxide functional dopamine derivative as monomers, were conjugated with small functional groups in a rewritable process. Reversible coding of the nitroxide functional microspheres by NRC and decoding through thermal alkoxyamine fission were monitored and characterized by electron paramagnetic resonance (EPR) spectroscopy and X-ray photoelectron spectroscopy (XPS). In addition, this nitroxide coating system was exploited in "grafting-to" polymer surface ligations of poly(methyl methacrylate) (PMMA) and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) in spatially confined areas. Polymer strands terminated with an Irgacure 2959 (2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone) photoinitiator were obtained through chain-transfer polymerization, and subsequently coupled to nitroxide-immobilized poly(dopamine) (PDA)-coated silicon substrates by using rapid photoclick NRC reactions. Light-driven polymer surface coding was visualized by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and XPS imaging.
Contemporary Photoligation Chemistry: The Visible Light Challenge
Publisher: Wiley
Date: 13-12-2018
Abstract: Catalyst-free and bond-forming light-induced reactions have seen an unprecedented renaissance in the realm of soft matter materials science due to their efficiency, spatio-temporal controllability and, sometimes, photoreversible nature. However, many of these reactions rely on the application of high energy UV light that can cause photo-degradation and is inapplicable in biological environments. If up-conversion systems or two-photon processes are to be avoided, strategies for red-shifting catalyst-free ligation technology are critically required. This Concept article introduces the reader to recent methods that lead to efficient, catalyst-free visible-light-induced ligation chemistry based on polyaromatic substituted photoreactive compounds-pyrene and anthracene-and, furthermore, emphasizes the broad and facile applicability of these molecules in polymeric material design. Concomitantly, we highlight that a careful action plot analysis of photochemical reactivity can provide deep insights into reactivity patterns, far beyond those suggested by the absorption spectrum. Indeed, we suggest that an action plot analysis is necessary for the evaluation of any photochemical system and its response to structural chemical changes.
A Photolithographic Approach to Spatially Resolved Cross-Linked Nanolayers
Publisher: American Chemical Society (ACS)
Date: 05-03-2015
DOI: 10.1021/LA505011J
Abstract: The preparation of cross-linked nanosheets with 1-2 nm thickness and predefined shape was achieved by lithographic immobilization of trimethacryloyl thioalkanoates onto the surface of Si wafers, which were functionalized with 2-(phenacylthio)acetamido groups via a photoinduced reaction. Subsequent cross-linking via free radical polymerization as well as a phototriggered Diels-Alder reaction under mild conditions on the surface led to the desired nanosheets. Electrospray ionization mass spectrometry (ESI-MS), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), as well as infrared reflection-absorption spectroscopy (IRRAS) confirmed the success of in idual surface-modification and cross-linking reactions. The thickness and lateral size of the cross-linked structures were determined by atomic force microscopy (AFM) for s les prepared on Si wafers functionalized with a self-assembled monolayer of 1H,1H,2H,2H-perfluorodecyl groups bearing circular pores obtained via a polymer blend lithographic approach, which led to the cross-linking reactions occurring in circular nanoareas (diameter of 50-640 nm) yielding an average thickness of 1.2 nm (radical cross-linking), 1.8 nm (radical cross-linking in the presence of 2,2,2-trifluoroethyl methacrylate as a comonomer), and 1.1 nm (photochemical cross-linking) of the nanosheets.
Free-radical copolymerization of styrene and m-isopropenyl-alpha,alpha '-dimethylbenzyl isocyanate studied by H-1 NMR kinetic experiments
Publisher: Wiley
Date: 27-02-2002
DOI: 10.1002/POLA.10195
Long‐lived intermediates in reversible addition–fragmentation chain‐transfer (RAFT) polymerization generated by γ radiation
Publisher: Wiley
Date: 03-2002
DOI: 10.1002/POLA.10194
Wavelength-Gated Photoreversible Polymerization and Topology Control
Publisher: American Chemical Society (ACS)
Date: 30-01-2020
DOI: 10.26434/CHEMRXIV.11760552.V1
Abstract: We exploit the wavelength dependence of [2+2] photocycloadditions and -reversions of styrylpyrene to exert unprecedented control over the photoreversible polymerization and topology of telechelic building blocks. Blue light affords high molar mass polymers that are stable at wavelengths exceeding 430 nm yet highly responsive to shorter wavelengths. UVB irradiation induces a rapid depolymerization yielding linear oligomers, whereas violet light generates cyclic entities. Different colors of light thus allow switching between a depolymerization that either proceeds through cyclic or linear topologies. The light-controlled topology formation was evidenced by correlation of mass spectrometry (MS) with size exclusion chromatography (SEC) and ion mobility data.
Introducing electrical conductivity to metal–organic framework thin films by templated polymerization of methyl propiolate
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR06848A
Abstract: Conductive SURMOF-composite thin films were successfully obtained by Pd-catalyzed polymerization of methyl propiolate and deeply investigated, finding evidence for depot release effects.
Computational prediction of the molecular configuration of three-dimensional network polymers
Publisher: Springer Science and Business Media LLC
Date: 28-06-2021
Access to Multiblock Copolymers via Supramolecular Host–Guest Chemistry and Photochemical Ligation
Publisher: American Chemical Society (ACS)
Date: 08-09-2015
Orthogonal Transformations on Solid Substrates: Efficient Avenues to Surface Modification
Publisher: Wiley
Date: 03-09-2009
Amphiphilic Block Copolymers Based on Poly(2‐acryloyloxyethyl phosphorylcholine) Prepared via RAFT Polymerisation as Biocompatible Nanocontainers
Publisher: Wiley
Date: 13-04-2004
Abstract: Amphiphilic block copolymers composed of poly(butyl acrylate) and poly(2-acryloyloxyethyl phosphorylcholine) have been prepared using reversible addition fragmentation transfer (RAFT) polymerisation. The conversion of the polymerisation was determined using online FT NIR spectroscopy. NMR spectroscopy was used not only to support the results obtained from FT NIR spectroscopy but also prove the formation of micelles. Due to the strong aggregation tendency of these block copolymers and the resulting difficulties concerning the molecular weight analysis test experiments were carried out replacing poly(2-acryloyloxyethyl phosphorylcholine) with poly(2-hydroxyethyl acrylate). Micelle size and the aggregation behaviour were investigated using dynamic light scattering. The sizes of the nanocontainers obtained were found to be influenced by the block length as well as the solvent leading to micelles in the range between 40 and 160 nm. The toxicity of the RAFT agent used was then analysed by cell growth inhibition tests.
Wavelength‐Gated Photochemical Synthesis of Phenalene Diimides
Publisher: Wiley
Date: 18-03-2021
Free radical propagation rate coefficients of N-containing methacrylates: Are we family?
Publisher: American Chemical Society (ACS)
Date: 11-11-2016
Light-sheet 3D microprinting via two-colour two-step absorption
Publisher: Springer Science and Business Media LLC
Date: 13-10-2022
Studying the Mechanism of Thioketone-Mediated Polymerization via Electrospray Ionization Mass Spectrometry
Publisher: Wiley
Date: 25-02-2009
DOI: 10.1002/POLA.23280
Abstract: The polymeric product spectrum generated in thioketone‐mediated free radical polymerization (TKMP) was analyzed via electrospray ionization mass spectrometry. Poly( n ‐butyl acrylate) s les were synthesized in the presence of the (commercially available) thioketone 4,4‐bis(dimethylamino)thiobenzophenone under variable reaction conditions in toluene solution at 80 °C. To unambiguously assign the mass spectra, the s les are prepared under variation of the monomer (going from n ‐butyl acrylate to ethyl acrylate) as well as by employing variable thermally decomposing initiators [i.e., 2,2′‐azoisobutyronitrile and azobis(cyclohexanecarbonitrile)]. In all mass spectra, significant amounts of the expected cross‐termination product, formed via bimolecular termination of propagating macroradicals with the dormant thioketone radical adduct (consisting of a propagating chain and the mediating thioketone) alongside conventional termination products can be identified. As the study was carried out on acrylate polymers, acrylate‐specific reaction products arising from intramolecular transfer reactions followed by β‐scission of the generated mid‐chain radicals are also identified in the mass spectra. In addition, a species congruent with the dormant thioketone radical adduct itself (oxidized to its cationic state) was identified. Products that could potentially be formed via a chain transfer mechanism cannot be identified. The results presented here thus support the earlier suggested TKMP mechanism involving a highly stabilized adduct radical which undergoes significant cross‐termination reactions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1864–1876, 2009
Spin capturing with Clickable nitrones: Generation of miktoarmed star polymers
Publisher: American Chemical Society (ACS)
Date: 16-03-2010
DOI: 10.1021/MA100263K
Hetero‐Diels–Alder Cycloaddition with RAFT Polymers as Bioconjugation Platform
Publisher: Wiley
Date: 02-09-2020
Direct Synthesis of Pyridyl Disulfide‐Terminated Polymers by RAFT Polymerization
Publisher: Wiley
Date: 30-01-2007
Degradation of RAFT polymers in a cyclic ether studied via high resolution ESI‐MS: Implications for synthesis, storage, and end‐group modification
Publisher: Wiley
Date: 09-10-2008
DOI: 10.1002/POLA.23050
Polymer Interfaces: Synthetic Strategies Enabling Functionality, Adaptivity, and Spatial Control
Publisher: American Chemical Society (ACS)
Date: 29-06-2016
One-pot synthesis of cyclopentadienyl endcapped poly(2-ethyl-2-oxazoline) and subsequent ambient temperature Diels–Alder conjugations
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CC14075B
Abstract: An efficient method for the preparation of cyclopentadienyl endcapped poly(2-ethyl-2-oxazoline) (PEtOx-Cp) via cationic ring-opening polymerization utilizing sodium cyclopentadienide as a termination agent is presented. Subsequent Diels-Alder reactions with N-substituted maleimides proceed quantitatively at ambient temperature. A block copolymer (PEtOx-b-PEG) is prepared employing maleimide terminated poly(ethylene glycol).
Synthesis of Cyclopentadienyl Capped Polyethylene and Subsequent Block Copolymer Formation Via Hetero Diels‐Alder (HDA) Chemistry
Publisher: Wiley
Date: 13-07-2011
Abstract: In the current contribution it is demonstrated - for the first time - that poly(ethylene) (M(n) = 1,400 as well as 2,800 g · mol(-1) , PDI = 1.2) can be readily equipped with highly reactive cyclopentadienyl (Cp) end groups. The Cp terminal poly(ethylene) can subsequently be reacted in an efficient hetero Diels-Alder (HDA) reaction with macromolecules (poly(isobornyl acrylate) (M(n) = 4,600 g · mol(-1) , PDI = 1.10) and poly(styrene) (M(n) = 6,300 g · mol(-1) , PDI = 1.13) featuring strongly electron withdrawing thiocarbonyl thio end groups, prepared via reversible addition fragmentation chain transfer (RAFT) polymerization employing benzylpyridin-2-yldithioformate (BPDF) as transfer agent. The resulting block copolymers have been analyzed via high-temperature size exclusion chromatography (SEC) as well as nuclear magnetic resonance (NMR) spectroscopy. The current system allows for the removal of the excess of the non-poly(ethylene) containing segment via filtration of the poly(ethylene)-containing block copolymer. However, the reaction temperatures need to be judiciously selected. Characterization of the generated block copolymers at elevated temperatures can lead - depending on the block copolymer type - to the occurrence of retro Diels-Alder processes. The present study thus demonstrates that RAFT-HDA ligation can be effectively employed for the generation of block copolymers containing poly(ethylene) segments.
Wellenlängengesteuerte dynamische kovalente Chemie
Publisher: Wiley
Date: 16-01-2018
Post‐Functionalization of Polymers via Orthogonal Ligation Chemistry
Publisher: Wiley
Date: 31-10-2014
Visible‐Light‐Reactive Single‐Chain Nanoparticles
Publisher: Wiley
Date: 26-04-2023
Abstract: We introduce a single‐chain nanoparticle (SCNP) system capable of catalyzing the photooxidation of nonpolar alkenes up to three times more efficiently than an equivalent small‐molecule photosensitizer at an identical concentration. Specifically, we construct a polymer chain constituted of poly(ethylene glycol) methyl ether methacrylate and glycidyl methacrylate which we compact via multifunctional thiol‐epoxide ligation and functionalize with Rose Bengal ( RB ) in a one pot reaction, affording SCNPs with a hydrophilic shell and hydrophobic photocatalytic regions. Photooxidation of the internal alkene in oleic acid proceeds under green light. RB confined within the SCNP is three times more effective for nonpolar alkenes than free RB in solution, which we hypothesize is due to the spatial proximity of the photosensitizing units to the substrate in the hydrophobic region. Our approach demonstrates that SCNP based catalysts can afford enhanced photocatalysis via confinement effects in a homogeneous reaction environment.
Well-defined star shaped polymer-fullerene hybrids via click chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B920806M
Design Criteria for Accurate Measurement of Bimolecular Radical Termination Rate Coefficients via the RAFT‐CLD‐T Method
Publisher: Wiley
Date: 02-12-2008
Steuerung der reversiblen Faltung von Einzelketten‐Nanopartikeln durch sichtbares Licht
Publisher: Wiley
Date: 03-08-2023
Abstract: In der vorliegenden Arbeit stellen wir Einzelketten‐Nanopartikel (ENPs) vor, die sich mit sichtbarem Licht ( λ max =415 nm) aus ihrem gefalteten Zustand vollständig zu dem entsprechenden linearen Ausgangspolymer entfalten lassen. Die ursprüngliche Faltung wird durch eine einfache Veresterungsreaktion des Polymerrückrats, bestehend aus Acrylsäure und Polyethylenglykol‐dekorierten Acrylateinheiten, erreicht. Die so eingeführten Bimaneinheiten ermöglichen eine photochemische Entfaltungsreaktion durch Esterspaltung. Die Faltung und das lichtinduzierte Entfalten läuft weitgehend ohne Nebenreaktionen ab und kann direkt mittels Größenausschlusschromatographie (GPC) sowie diffusionsgeordneter NMR‐Spektroskopie (DOSY) durch die Veränderung des hydrodynamischen Radius ( R H ) nachverfolgt werden. Besonders hervorzuheben ist die Reversibilität sowohl der Faltung als auch der lichtinduzierten Entfaltung, die durch den hohen Umsatz bei der photochemischen Esterspaltung erreicht werden kann. Da die Photolyse in wässrigem Medium abläuft, könnte sich das System für die Untersuchung der Entfaltung von ENPs im biologischen Kontext eignen.
Synthesis of star and H-shape polymers via a combination of cobalt-mediated radical polymerization and nitrone-mediated radical coupling reactions
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00297J
Abstract: Via the combination of nitrone-mediated radical coupling and cobalt-mediated radical polymerization, mid-chain functionalized polymers are obtained that can be assembled into H-shaped polymers.
Mapping Free Radical Reactivity: A High-Resolution Electrospray Ionization−Mass Spectrometry Study of Photoinitiation Processes in Methyl Methacrylate Free Radical Polymerization
Publisher: American Chemical Society (ACS)
Date: 14-11-2006
DOI: 10.1021/MA0616559
Making and Breaking Chemical Bonds by Chemiluminescence
Publisher: Wiley
Date: 07-08-2018
Abstract: Chemiluminescent (CL) reactions are powerful analytical tools and are present in commercially available everyday objects such as glow sticks. Herein, the photons generated by chemiluminescence are exploited to induce covalent bond breakage and formation, using a chemically generated photonic field at ambient temperature through space as energy transducer. Remarkably, the generated photons enable both the cleavage of species generating radicals as well as the execution of [2 + 2] cycloadditions, demonstrating that disparate types of reactions can be triggered. The herein-presented photochemical concept establishes the field of CL-induced photochemistry, which is poised to enable photochemical transformations in situations where physical light sources, such as l s, LEDs, and lasers cannot be employed, including in biological environments.
Supercharging Synthetic Polymers: Mass Spectrometric Access to Nonpolar Synthetic Polymers
Publisher: American Chemical Society (ACS)
Date: 04-10-2017
Efficient access to multi‐arm star block copolymers by a combination of ATRP and RAFT‐HDA click chemistry
Publisher: Wiley
Date: 11-03-2009
DOI: 10.1002/POLA.23299
Nano‐ and Micro‐Engineering of Ordered Porous Blue‐Light‐Emitting Films by Templating Well‐Defined Organic Polymers Around Condensing Water Droplets
Publisher: Wiley
Date: 07-08-2003
RAFT Mediated Polymerization of Methyl Methacrylate Initiated by Bergman Cyclization: Access to High Molecular Weight Narrow Polydispersity Polymers
Publisher: Wiley
Date: 24-01-2011
Abstract: The first RAFT mediated polymerization of methyl methacrylate initiated by diradicals derived from Bergman cyclization was performed employing 3,4-benzocyclodec-3-ene-1,5-diyne (BCDY) as diradical source and cyanoisopropyldithiobenzoate (CPDB) as RAFT agent. The polymerization was conducted in bulk at 80 °C for 3 h. The concentration of the enediyne was kept constant at 3.0 x 10⁻² mol · L⁻¹ and the RAFT agent concentration was varied between 0.0 mol · L⁻¹ and 2.4 x 10⁻¹ mol · L⁻¹. A detailed ESI-MS analysis reveals the absence of intramolecular termination reactions (ring formation) in the RAFT mediated system, which usually makes diradicalic initiation unfavorable. The presence of polymeric chains propagating at both ends could be confirmed. The conversion of the RAFT mediated polymerization was up to more than two times higher than the RAFT free polymerization at identical conditions. Thus, polymers with narrow polydispersities (1.1 ≤ PDI ≤ 1.5) even at very high molecular weights (near 400,000 Da) were obtained within modest reaction times.
Mark-Houwink Parameters for the Universal Calibration of Acrylate, Methacrylate and Vinyl Acetate Polymers Determined by Online Size-Exclusion Chromatography-Mass Spectrometry
Publisher: Wiley
Date: 26-02-2010
Shell-Cross-Linked Vesicles Synthesized from Block Copolymers of Poly(d ,l -lactide) and Poly(N-isopropyl acrylamide) as Thermoresponsive Nanocontainers
Publisher: American Chemical Society (ACS)
Date: 03-11-2004
DOI: 10.1021/LA0484016
Abstract: A polylactide (D,L-PLA) macroRAFT agent was prepared by utilizing a hydroxyl-functional trithiocarbonate as a coinitiator for the ring-opening polymerization. The length of the resultant polymer was controlled by the concentration of the coinitiator leading to the formation of two PLA polymers with M(n) = 12500 g mol(-)(1) (PDI = 1.46) and M(n) = 20500 g mol(-)(1) (PDI = 1.38) each with omega-trithiocarbonate functionality. Chain extension of PLA via the RAFT (free radical) polymerization of N-isopropyl acrylamide (NIPAAm) resulted in the formation of hiphilic block copolymers with the PNIPAAm block increasing in size with conversion. TEM measurements of the aggregates obtained by self-organization of the block copolymers in aqueous solutions indicated the formation of vesicles. The sizes of these aggregates were influenced by the ratio of both blocks and the molecular weight of each block. The lower critical solution temperature (LCST) of the block copolymer was largely unaffected by the size of each block. UV turbidity measurements indicated a higher LCST for the block copolymers than for the corresponding PNIPAAm homopolymers. Stabilization of the vesicles was attained by a cross-linking chain extension of the PNIPAAm block using hexamethylene diacrylate. As the trithiocarbonate group was located between the PLA and PNIPAAm blocks, the chain extension resulted in a cross-linked layer between the core and corona of the vesicles.
Propagation and termination rate coefficients in N-vinylcarbazole free radical polymerization obtained via 440 nm pulsed laser and online H-1 NMR kinetic experiments
Publisher: Wiley
Date: 04-2003
Abstract: Propagation rate coefficients, k p , of N ‐vinylcarbazole in solution have been determined via visible light pulsed‐laser polymerization over a wide temperature range ( E A = 25.3 ± 5 kJ · mol −1 , A = 1.0 × 10 8 L · mol −1 · s −1 ). The k p data set was used to deduce (average) termination rate coefficients via 1 H NMR spectroscopic kinetic experiments and the corresponding Arrhenius parameters ( E A = −8.5 kJ · mol −1 ± 8 kJ · mol −1 ). Temperature dependence of the propagation rate coefficient, k p , in the free radical solution polymerization of NVC. The graph shows the data from 355 and 440 nm initiation as well as data previously obtained by Yamamoto et al. 5 The three sets of data have been analyzed separately (for details see text). magnified image Temperature dependence of the propagation rate coefficient, k p , in the free radical solution polymerization of NVC. The graph shows the data from 355 and 440 nm initiation as well as data previously obtained by Yamamoto et al. 5 The three sets of data have been analyzed separately (for details see text).
A facile avenue to conductive polymer brushes via cyclopentadiene–maleimide Diels–Alder ligation
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC44683B
Abstract: Cyclopentadienyl end-capped poly(3-hexylthiophene) was employed to fabricate conductive surface tethered polymer brushes via a facile route based on cyclopentadiene-maleimide Diels-Alder ligation. The efficient nature of the Diels-Alder ligation was further combined with a biomimetic polydopamine-assisted functionalization of surfaces, making it an access route of choice for P3HT surface immobilization.
Fusing Light-Induced Step-Growth Processes with RAFT Chemistry for Segmented Copolymer Synthesis: A Synergetic Experimental and Kinetic Modeling Study
Publisher: American Chemical Society (ACS)
Date: 15-08-2017
A Self-Catalyzed Visible Light Driven Thiol Ligation
Publisher: American Chemical Society (ACS)
Date: 06-05-2021
DOI: 10.1021/JACS.1C03213
Fructose-Coated Nanodiamonds: Promising Platforms for Treatment of Human Breast Cancer
Publisher: American Chemical Society (ACS)
Date: 03-08-2016
DOI: 10.1021/ACS.BIOMAC.6B00754
Abstract: Well-defined carboxyl end-functionalized glycopolymer Poly(1-O-methacryloyl-2,3:4,5-di-O-isopropylidene-β-d-fructopyranose) (Poly(1-O-MAipFru)62) has been prepared via reversible addition-fragmentation chain transfer polymerization and grafted onto the surface of amine-functionalized nanodiamonds via a simple conjugation reaction. The properties of the nanodiamond-polymer hybrid materials ND-Poly(1-O-MAFru)62 are investigated using infrared spectroscopy, thermogravimetric analysis, dynamic light scattering, and transmission electron microscopy. The dispersibility of the nanodiamonds in aqueous solutions is significantly improved after the grafting of the glycopolymer. More interestingly, the cytotoxicity of amine-functionalized nanodiamonds is significantly decreased after decoration with the glycopolymer even at a high concentration (125 μg/mL). The nanodiamonds were loaded with doxorubicin to create a bioactive drug delivery carrier. The release of doxorubicin was faster in media of pH 5 than media of pH 7.4. The nanodiamond drug delivery systems with doxorubicin are used to treat breast cancer cells in 2D and 3D models. Although the 2D cell culture results indicate that all nanodiamonds-doxorubicin complexes are significantly less toxic than free doxorubicin, the glycopolymer-coated nanodiamonds-doxorubicin show higher cytotoxicity than free doxorubicin in the 3D spheroids after treatment for 8 days. The enhanced cytotoxicity of Poly(1-O-MAFru)62-ND-Dox in 3D spheroids may result from the sustained drug release and deep penetration of these nanocarriers, which play a role as a "Trojan Horse". The massive cell death after 8-day incubation with Poly(1-O-MAFru)62-ND-Dox demonstrates that glycopolymer-coated nanodiamonds can be promising platforms for breast cancer therapy.
A Sunlight-Induced Click Reaction as an Efficient Route to Cyclic Aliphatic Polyesters
Publisher: Wiley
Date: 17-04-2015
The Use of Novel F-RAFT Agents in High Temperature and High Pressure Ethene Polymerization: Can Control be Achieved?
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/CH07200
Abstract: Simulations are employed to establish the feasibility of achieving controlled/living ethene polymerizations. Such simulations indicate that reversible addition–fragmentation chain transfer (RAFT) agents carrying a fluorine Z group may be suitable to establish control in high-pressure high-temperature ethene polymerizations. Based on these simulations, specific fluorine (F-RAFT) agents have been designed and tested. The initial results are promising and indicate that it may indeed be possible to achieve molecular weight distributions with a polydispersity being significantly lower than that observed in the conventional free radical process. In our initial trials presented here (using the F-RAFT agent isopropylfluorodithioformate), a correlation between the degree of polymerization and conversion can indeed be observed. Both the lowered polydispersity and the linear correlation between molecular weight and conversion indicate that control may in principle be possible.
Disulfone Cross-Linkers for λ-Orthogonal Photoinduced Curing and Degradation of Polymeric Networks
Publisher: American Chemical Society (ACS)
Date: 14-12-2016
Grafting thermoresponsive polymers onto honeycomb structured porous films using the RAFT process
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B807495J
Free-Radical Propagation Rate Coefficients of Dodecyl Methacrylate Deduced from Electron Spin Resonance Experiments
Publisher: American Chemical Society (ACS)
Date: 22-09-1998
DOI: 10.1021/MA980542P
Dual-Wavelength Gated oxo-Diels–Alder Photoligation
Publisher: American Chemical Society (ACS)
Date: 23-02-2021
Implementing the reversible addition–fragmentation chain transfer process in PREDICI
Publisher: Wiley
Date: 02-02-2004
DOI: 10.1002/POLA.11089
A printable thermally activated delayed fluorescence polymer light emitting diode
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TC02735A
Abstract: We report the first ink-jet printed thermally activated delayed fluorescence (TADF) polymer organic light emitting diode (OLED).
A focus on how latent “codons” are unravelled in synthetic copolymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3SC90087H
Abstract: We explore and comment on a key development using advanced mass spectrometric methods coupled with advanced algorithmic learning that can assist in analysing complex copolymers.
Visible-light reversible photopolymerisation
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY01119C
Abstract: Herein, we introduce a scalable photopolyaddition polymerisations using the pyrene-chalcone [2+2]-cycloaddition and monitor the photodepolymerisation process via an online photoflow – electrospray ionisation mass spectrometry setup.
The living dead – common misconceptions about reversible deactivation radical polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6MH00265J
Abstract: We illustrate common misconceptions and errors when interpreting polymerization data from ‘Living/controlled’ radical polymerization, preferably termed ‘reversible deactivation radical polymerization’ (RDRP). Avoiding the discussed errors leads to better defined materials for soft matter materials applications.
An Update on the Pivotal Role of Kinetic Modeling for the Mechanistic Understanding and Design of Bulk and Solution RAFT Polymerization
Publisher: Wiley
Date: 10-10-2016
Thioketone‐Mediated Polymerization of Butyl Acrylate: Controlling Free‐Radical Polymerization via a Dormant Radical Species
Publisher: Wiley
Date: 16-03-2007
Thermally responsive core–shell microparticles and cross-linked networks based on nitrone chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY20272G
Abstract: Complex cross-linked soluble architectures are generated using nitrone mediated chemistry and are subsequently cleaved into network fragments. Nitrone mediated reactions are additionally applied for the synthesis of stimuli-responsive microspheres.
Controlling Chain Coupling and Single‐Chain Ligation by Two Colours of Visible Light
Publisher: Wiley
Date: 12-02-2019
Abstract: While photochemical synthesis offers access to spatiotemporal reaction control, its potential to selectively address specific reactions by the colour of light is usually limited by ubiquitous spectral absorption overlaps of the reactive groups. Herein, a new concept is introduced that actively suppresses one ligation reaction by triggering the cycloreversion of the [2+2] cycloaddition of styrylpyrene. Combination of the photoreversible styrylpyrene chemistry with the [4+4] cycloaddition of 9-triazolylanthracene makes it possible to initially induce chain coupling using UV light and to subsequently ligate the formed single-chain nanoparticle (SCNP) with a second polymer chain using blue light. Seizing upon the first sequence-independent λ-orthogonal reactivity established here, the same macromolecular architecture was obtained in reverse irradiation sequence, by blue and subsequent violet light irradiation-completely foregoing high-energy UV light.
Ultra Rapid Approaches to Mild Macromolecular Conjugation
Publisher: Wiley
Date: 13-07-2010
Abstract: In light of the increasing demand for ultra rapid and mild conjugation chemistries for use in macromolecular chemistry, the present Feature Article provides a critical overview of the very latest developments in this field. The principal aim, therefore, is the provision of a quick selection guide to aid in the formulation of a design strategy for novel functional materials and to provide recommendations for future developments in the chemistries discussed.
Living Radical Polymerization of Ethylene: A Challenge Overcome?
Publisher: Wiley
Date: 22-08-2014
Molecular composite materials formed from block copolymers containing a side-chain liquid crystalline segment and an amorphous styrene/maleic anhydride segment
Publisher: Elsevier BV
Date: 10-2004
With polymer photoclicks to fluorescent microspheres
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8MH01078A
Abstract: A new method of additive-free particle synthesis facilitates the rapid preparation of inherently fluorescent microspheres via photoactive prepolymers.
Combining Photodeprotection and Ligation into a Dual‐Color Gated Reaction System
Publisher: Wiley
Date: 16-10-2020
M24+ paddlewheel clusters as junction points in single-chain nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8PY01486H
Abstract: A straightforward approach to incorporate copper and molybdenum dimetallic clusters into well-defined single-chain nanoparticles, featuring unique paddlewheel structures as junction points, is introduced.
Wellenlängen‐Orthogonale Versteifung von Hydrogel‐Netzwerken mit sichtbarem Licht
Publisher: Wiley
Date: 15-02-2022
Abstract: Hierin stellen wir die wellenlängen‐orthogonale Vernetzung von Hydrogelnetzwerken unter Verwendung zweier stark rotverschobener Chromophore vor, nämlich Acrylpyren (AP, λ Aktivierung =410–490 nm) und Styrylpyrido[2,3‐b]pyrazin (SPP, λ Aktivierung =400–550 nm), die eine [2+2]‐Photocycloaddition im sichtbaren Wellenlängenbereich eingehen können. Die Photoreaktivität der SPP‐Gruppe ist pH‐abhängig, wobei eine saure Umgebung die Cycloaddition hemmt. Durch den Einsatz eines auf Spiropyran basierenden Photosäuregenerator mit geeigneter Absorptionswellenlänge sind wir in der Lage, die Aktivierungswellenlänge der SPP‐Gruppe auf den grünen Wellenlängenbereich ( λ Aktivierung =520–550 nm) zu beschränken, was eine wellenlängen‐orthogonale Aktivierung der AP‐Gruppe ermöglicht. Unser wellenlängen‐orthogonales photochemisches System wurde erfolgreich zur Entwicklung von Hydrogelen eingesetzt, deren Steifigkeit unabhängig voneinander durch grünes oder blaues Licht eingestellt werden kann.
A Detailed On‐Line FT/NIR and 1H NMR Spectroscopic Investigation into Factors Causing Inhibition in Xanthate‐Mediated Vinyl Acetate Polymerization
Publisher: Wiley
Date: 26-04-2004
Synthesis of macromonomers via catalytic chain transfer (CCT) polymerization and their characterization via NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS)
Publisher: Wiley
Date: 04-2004
Wavelength-Dependent Photochemistry of Oxime Ester Photoinitiators
Publisher: American Chemical Society (ACS)
Date: 02-03-2017
Facile Synthesis and In-Depth Characterization of Polymethacrylimides with Tunable Properties
Publisher: Wiley
Date: 16-06-2020
Fabrication of 3D gold/polymer conductive microstructures via direct laser writing (Conference Presentation)
Publisher: SPIE
Date: 19-04-2017
DOI: 10.1117/12.2256873
Chemiluminescent self-reporting supramolecular transformations on macromolecular scaffolds
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY00332H
Abstract: We introduce the synthesis of a self-reporting system with chemiluminescent output, which is regulated via dynamic supramolecular complex formation.
A Facile Route to Boronic Acid Functional Polymeric Microspheres via Epoxide Ring Opening
Publisher: Wiley
Date: 27-04-2012
Abstract: Boronic acid-functionalized microspheres are prepared for the first time via mild epoxide ring opening based on porous cross-linked polymeric microspheres (diameter ≈ 10 μm, porosity ≈ 1000 Å). Quantitative chemical analysis by XPS and EA evidences that there is a greater functionalization with boronic acid when employing a sequential synthetic method [1.7 atom% boron (XPS) 1.12 wt% nitrogen (EA)] versus a one-pot synthetic method [0.2 atom% boron (XPS) 0.60 wt% nitrogen (EA)] yielding grafting densities ranging from approximately 2.5 molecules of boronic acid per nm(2) to 1 molecule of boronic acid per nm(2), respectively. Furthermore, the boronic acid-functionalized microspheres are conjugated with a novel fluorescent glucose molecule demonstrating a homogeneous spatial distribution of boronic acid.
Kinetic Analysis of Reversible Addition Fragmentation Chain Transfer (RAFT) Polymerizations: Conditions for Inhibition, Retardation, and Optimum Living Polymerization
Publisher: Wiley
Date: 11-2002
DOI: 10.1002/1521-3919(20021101)11:8<823::AID-MATS823>3.0.CO;2-R
Degradable Redox-Responsive Polyolefins
Publisher: American Chemical Society (ACS)
Date: 04-02-2021
UV Light and Temperature Responsive Supramolecular ABA Triblock Copolymers via Reversible Cyclodextrin Complexation
Publisher: American Chemical Society (ACS)
Date: 02-2013
DOI: 10.1021/MA302386W
Chemical approaches to synthetic polymer surface biofunctionalization for targeted cell adhesion using small binding motifs
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2SM07407A
Photolithographic Encoding of Metal Complexes
Publisher: Wiley
Date: 28-08-2015
Abstract: A platform technology for the creation of spatially resolved surfaces encoded with a monolayer consisting of different metal complexes was developed. The concept entails the light-triggered activation of a self- assembled monolayer (SAM) of UV-labile anchors, that is, phenacylsulfides, and the subsequent cycloaddition of selected diene-functionalized metal complexes at defined areas on the surface. The synthesis and characterization of the metal complexes for the UV-light assisted anchoring on the surface and a detailed study of a short-chain oligomer model system in solution confirm the high efficiency of the photoreaction. The hybrid materials obtained by this concept can potentially be utilized for the design of highly valuable catalytic or (opto-)electronic devices.
Flexible Ink‐Jet Printed Polymer Light‐Emitting Diodes using a Self‐Hosted Non‐Conjugated TADF Polymer
Publisher: Wiley
Date: 26-04-2023
Abstract: Thermally activated delayed fluorescent (TADF) emitters have become the leading emissive materials for highly efficient organic light‐emitting diodes (OLEDs). The deposition of these materials in scalable and cost‐effective ways is paramount when looking toward the future of OLED applications. Herein, a simple OLED with fully solution‐processed organic layers is introduced, where the TADF emissive layer is ink‐jet printed. The TADF polymer has electron and hole conductive side chains, simplifying the fabrication process by removing the need for additional host materials. The OLED has a peak emission of 502 nm and a maximum luminance of close to 9600 cd m −2 . The self‐hosted TADF polymer is also demonstrated in a flexible OLED, reaching a maximum luminance of over 2000 cd m −2 . These results demonstrate the potential applications of this self‐hosted TADF polymer in flexible ink‐jet printed OLEDs and, therefore, for a more scalable fabrication process.
Hierarchical Nacre Mimetics with Synergistic Mechanical Properties by Control of Molecular Interactions in Self‐Healing Polymers
Publisher: Wiley
Date: 10-06-2015
Abstract: Designing the reversible interactions of biopolymers remains a grand challenge for an integral mimicry of mechanically superior biological composites. Yet, they are the key to synergistic combinations of stiffness and toughness by providing sacrificial bonds with hidden length scales. To address this challenge, dynamic polymers were designed with low glass-transition temperature T(g) and bonded by quadruple hydrogen-bonding motifs, and subsequently assembled with high-aspect-ratio synthetic nanoclays to generate nacre-mimetic films. The high dynamics and self-healing of the polymers render transparent films with a near-perfectly aligned structure. Varying the polymer composition allows molecular control over the mechanical properties up to very stiff and very strong films (E≈45 GPa, σ(UTS)≈270 MPa). Stable crack propagation and multiple toughening mechanisms occur in situations of balanced dynamics, enabling synergistic combinations of stiffness and toughness. Excellent gas barrier properties complement the multifunctional property profile.
Characterizing single chain nanoparticles (SCNPs): a critical survey
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY01278K
Abstract: We provide the results of a critical literature survey on the reported sizes of single chain polymer nanoparticles (SCNPs) employing different techniques.
Supramolecular three-armed star polymers via cyclodextrin host–guest self-assembly
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY20293J
Cover Picture: Dynamic Macromolecular Material Design—The Versatility of Cyclodextrin‐Based Host–Guest Chemistry (Angew. Chem. Int. Ed. 29/2017)
Publisher: Wiley
Date: 06-2017
Dendrimers as Scaffolds for Reversible Addition Fragmentation Chain Transfer (RAFT) Agents: a Route to Star-Shaped Block Copolymers
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/CH05036
Abstract: Star-shaped block copolymers of styrene and n-butyl acrylate having three, six, and twelve pendent arms were successfully synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. Dendritic cores (based on 1,1,1-trimethylolpropane) of generation 0, 1, and 2 have been functionalized with 3-benzylsulfanylthiocarbonylsulfanylpropionic ester groups and have subsequently been employed to mediate the polymerization of styrene and n-butyl acrylate to generate macro-star-RAFT agents as starting materials for chain extension. The chain extension of the macro-star-RAFT agents with either styrene or n-butyl acrylate by bulk free radical polymerization at 60°C gives narrowly distributed polymer (final polydispersities close to 1.2) increasing linearly in molecular weight with increasing monomer-to-polymer conversion. However, with an increasing number of arms (i.e., when going from three- to twelve-armed star polymers), the chain extension becomes significantly less efficient. The molecular weight of the generated block copolymers was assessed using 1H NMR spectroscopy as well as size exclusion chromatography calibrated with linear polystyrene standards. The hydrodynamic radius, Rh, of the star block copolymers as well as the precursor star polymers was determined in tetrahydrofuran by dynamic light scattering (90°) at 25°C. Interestingly, the observed Rh–Mn relationships indicate a stronger dependence of Rh on Mn for poly(butyl acrylate) stars than for the corresponding styrene polymers. Rh increases significantly when the macro-star-RAFT agent is chain extended with either styrene or n-butyl acrylate.
Polymer surface patterningvia Diels–Alder trapping of photo-generated thioaldehydes
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2CC37651B
Abstract: An efficient method for polymer surface patterning via Diels-Alder trapping of photo-generated thioaldehydes is presented. It is demonstrated that thioaldehyde end-groups generated by photolysis of phenacyl sulfides can be quantitatively trapped with various dienes. Poly(ethylene glycol) is immobilized on a surface in a spatially controlled fashion via irradiation through a shadow mask.
Kinetic Monte Carlo Modeling Extracts Information on Chain Initiation and Termination from Complete PLP-SEC Traces
Publisher: American Chemical Society (ACS)
Date: 13-02-2017
Influences of the Structural Design of RAFT Agents on Living Radical Polymerization Kinetics
Publisher: American Chemical Society
Date: 26-06-2003
Radical addition to thioketones: Computer-aided design of spin traps for controlling free-radical polymerization
Publisher: American Chemical Society (ACS)
Date: 22-09-2006
DOI: 10.1021/CT600128T
Abstract: An extensive study has been undertaken of the radical affinity of a number of thioketones (S [Formula: see text] C(X)(Y)) with the aim of selecting combinations of X and Y that render the substrate suitable for the mediation of free radical polymerizations. Using high level ab initio molecular orbital calculations, enthalpies at 0 K were determined for the reactions R(•) + S [Formula: see text] C(X)(Y) → R-S-C(•)(X)(Y) for R(•) = CH3, CH2OH, CH2CN, and benzyl, in reactions with a variety of thioketones, including various combinations of X and Y taken from H, CH3, Ph, CN, OCH3, C(CH3)3 and para-CN-Ph as well as several compounds in which the X and Y are bonded, namely xanthene-9-thione, fluorine-9-thione, and cyclopenta[def]phenanthrene-4-thione. The radical affinities of the various thioketones has been discussed in terms of the radical stabilization energies (RSEs) of the adduct radicals and stabilities of the S [Formula: see text] C bonds. From these studies, the two thioketones S [Formula: see text] C(CN)(Ph) and fluorene-9-thione were selected as being potentially suitable candidates for use in controlling free radical polymerizations due to their high radical affinities. However, based on transition state theory calculations of the rate coefficients for homo/copolymerization of S [Formula: see text] C(CN)(Ph) with itself and styrene at 333.15 K, this substrate was deemed to be unsuitable, as it was likely to undergo side reactions. Instead, the more-hindered fluorine-9-thione was identified as the ideal thioketone, and the equilibrium constants at 333.15 K for the reactions of the styryl and vinyl acetate dimer radicals with fluorine-9-thione were made. These two reactions, at 333.15 K, displayed equilibrium constants in the vicinity of 10(14) L mol(-)(1) and 10(16) L mol(-)(1), respectively, indicating that there is significant scope within the thioketone class of compounds to mediate free radical polymerizations via radical stability alone.
Photochemical Generation of Light Responsive Surfaces
Publisher: Wiley
Date: 12-03-2013
Spatially‐Resolved Multiple Metallopolymer Surfaces by Photolithography
Publisher: Wiley
Date: 06-12-2018
Abstract: A tetrazole‐based photoligation protocol for the spatially‐resolved encoding of various defined metallopolymers onto solid surfaces is introduced. By using this approach, fabrication of bi‐ and trifunctional metallopolymer surfaces with different metal combinations were achieved. Specifically, α‐ω‐functional copolymers containing bipyridine as well as triphenylphosphine ligands were synthesized through reversible addition‐fragmentation chain transfer (RAFT) polymerization, and subsequently metal loaded to afford metallopolymers of the widely‐used metals gold, palladium, and platinum. Spatially‐resolved surface attachment was achieved by means of a nitrile imine‐mediated tetrazole‐ene cycloaddition (NITEC) based photoligation protocol, exploiting tethered tetrazoles and metallopolymers equipped with a maleimide chain terminus. Metallopolymer coated surfaces with three different metals were prepared and characterized by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and spatially‐resolved X‐ray photoelectron spectroscopy (XPS) mapping, supporting the preserved chemical composition of the surface‐bound metallopolymers. The established photochemical technology platform for arbitrary spatially‐resolved metallopolymer surface designs enables the patterning of multiple metallopolymers onto solid substrates. This allows for the assembly of designer metallopolymer substrates.
Selective dispersion of single-walled carbon nanotubes via easily accessible conjugated click polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY20161E
Wavelength selective polymer network formation of end-functional star polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5CC09444E
Abstract: A wavelength selective technique for light-induced network formation is introduced, combining RAFT for precursor and DLW for 3D-structure generation.
λ‐Orthogonal Pericyclic Macromolecular Photoligation
Publisher: Wiley
Date: 23-01-2015
Abstract: A photochemical strategy enabling λ-orthogonal reactions is introduced to construct macromolecular architectures and to encode variable functional groups with site-selective precision into a single molecule by the choice of wavelength. λ-Orthogonal pericyclic reactions proceed independently of one another by the selection of functional groups that absorb light of specific wavelengths. The power of the new concept is shown by a one-pot reaction of equimolar quantities of maleimide with two polymers carrying different maleimide-reactive endgroups, that is, a photoactive diene (photoenol) and a nitrile imine (tetrazole). Under selective irradiation at λ=310-350 nm, any maleimide (or activated ene) end-capped compound reacts exclusively with the photoenol functional polymer. After complete conversion of the photoenol, subsequent irradiation at λ=270-310 nm activates the reaction of the tetrazole group with functional enes. The versatility of the approach is shown by λ-orthogonal click reactions of complex maleimides, functional enes, and polymers to the central polymer scaffold.
Adding Spatial Control to Click Chemistry: Phototriggered Diels–Alder Surface (Bio)functionalization at Ambient Temperature
Publisher: Wiley
Date: 09-12-2011
Reversible Addition Fragmentation Chain Transfer (RAFT) and Hetero-Diels−Alder Chemistry as a Convenient Conjugation Tool for Access to Complex Macromolecular Designs
Publisher: American Chemical Society (ACS)
Date: 20-05-2008
DOI: 10.1021/MA8002328
Multifunctional nacre-like materials
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3MH01015E
3D Printed Microstructures Erasable by Darkness
Publisher: Wiley
Date: 26-06-2022
Abstract: To advance the applications of direct laser writing (DLW), adaptability of the printed structure is critical, prompting a shift toward printing structures that are comprised of different materials, and/or can be partially or fully erased on demand. However, most structures that contain these features are often printed by complex processes or require harsh developing techniques. Herein, a unique photoresist for DLW is introduced that is capable of printing 3D microstructures that can be erased by exposure to darkness. Specifically, microstructures based on light‐stabilized dynamic materials are fabricated that remain stable when continously irradiated with green light, but degrade once the light source is switched off. The degradation and light stabilization properties of the printed materials are analyzed in‐depth by time‐lapse scanning electron microscopy. It is demonstrated that these resists can be used to impart responsive behavior onto the printed structure, and –critically– as a temporary locking mechanism to control the release of moving structural features.
Contemporary Mass Spectrometry and the Analysis of Synthetic Polymers: Trends, Techniques and Untapped Potential
Publisher: Wiley
Date: 12-07-2010
Fusing Catechol-Driven Surface Anchoring with Rapid Hetero Diels–Alder Ligation
Publisher: American Chemical Society (ACS)
Date: 24-10-2014
DOI: 10.1021/MZ5006469
Abstract: We fuse the surface anchoring abilities of catechols with the rapid ligating nature of thiocarbonyl thio-based hetero-Diels-Alder (HDA) reactions via the synthesis of a new small molecule (HDA-DOPA-Cp) combining a HDA moiety with a catechol. Inspired by the mechanism of strong adhesion of marine mussels, we employed catechols as anchors to attach HDA ligation points to silicon wafers. The latter was exploited to generate a base for the HDA reactions on the surface employing α-cyclopentadiene (Cp) functional polymers such as poly(ethylene glycol)-Cp (PEG-Cp) and poly(trifluoro ethyl methacrylate)-Cp (PTFEMA-Cp) as dienes. By utilizing the fast and efficient HDA chemistry in combination with catechol anchoring groups, a new method for creating functional surfaces was developed.
Chemiluminescent read-out of para-fluoro-thiol reaction events
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC06356H
Abstract: We exploit the fluoride that is released via the para -fluoro-thiol reaction (PFTR) to cleave silyl ethers, turning the PFTR into an effective self-reporting chemiluminescence (CL) probe.
Enhanced Ionization in Electrospray Ionization Mass Spectrometry of Labile End-Group-Containing Polystyrenes Using Silver(I) Tetrafluoroborate as Doping Salt
Publisher: American Chemical Society (ACS)
Date: 21-02-2008
DOI: 10.1021/MA702163V
Enhanced spin capturing polymerization: An efficient and versatile protocol for controlling molecular weight distributions
Publisher: Wiley
Date: 26-09-2008
DOI: 10.1002/POLA.23025
Modeling for Polymer Design
Publisher: Wiley
Date: 21-10-2009
Transfer and propagation reactions in free-radical copolymerization
Publisher: Wiley
Date: 06-2002
DOI: 10.1002/1521-3900(200206)182:1<131::AID-MASY131>3.0.CO;2-C
Polystyrene comb polymers built on cellulose or poly(styrene-co-2-hydroxyethylmethacrylate) backbones as substrates for the preparation of structured honeycomb films
Publisher: Elsevier BV
Date: 10-2005
Low Temperature Aqueous Living/Controlled (RAFT) Polymerization of Carboxybetaine Methacrylamide up to High Molecular Weights
Publisher: Wiley
Date: 03-06-2011
Abstract: Among the class of zwitterionic polymers poly(carboxybetaine)s (poly(CB)s) are unique, emerging as the only ultra-low fouling materials known allowing the preparation of biosensors, fouling resistant nanoparticles, and non-adhesive surfaces for bacteria. Poly(carboxybetaine methacrylate) and poly(carboxybetaine acrylamide) have been prepared via atom transfer radical polymerization (ATRP), however a polymerization with living characteristics has not been achieved yet. Herein, the first successful living/controlled reversible addition fragmentation transfer (RAFT) polymerization of (3-methacryloylamino-propyl)-(2-carboxy-ethyl)-dimethyl-ammonium (carboxybetaine methacrylamide) (CBMAA-3) in acetate buffer (pH 5.2) at 70 and 37 °C is reported. The polymerization afforded very high molecular weight polymers (determined by absolute size exclusion chromatography, close to 250,000 g·mol(-1) in less than 6 h) with low PDI (<1.3) at 70 °C. The polymerization was additionally carried out at 37 °C allowing to achieve yet lower PDIs (1.06 ≤ PDI ≤ 1.15) even at 90% conversion, demonstrating the suitability of the polymerization conditions for bioconjugate grafting. The living character of the polymerization is additionally evidenced by chain extending poly(CBMAA-3) at 70 and 37 °C. Block copolymerization from biologically relevant poly[N-(2-hydroxypropyl)methacrylamide] macroCTAs was additionally performed.
(Bio)Molecular Surface Patterning by Phototriggered Oxime Ligation
Publisher: Wiley
Date: 13-08-2012
Abstract: Making light work of ligation: A novel method utilizes light for oxime ligation chemistry. A quantitative, low-energy photodeprotection generates aldehyde, which subsequently reacts with aminooxy moieties. The spatial control allows patterning on surfaces with a fluoro marker and GRGSGR peptide, and can be imaged by time-of-flight secondary-ion mass spectrometry.
Macromolecular Engineering via
RAFT
Chemistry: From Sequential to Modular Design
Publisher: Wiley
Date: 15-02-2012
DOI: 10.1002/9783527603978.MST0431
Abstract: The sections in this article are
Light-driven nitrile imine-mediated tetrazole–ene cycloaddition as a versatile platform for fullerene conjugation
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC05507E
Abstract: An efficient methodology for modular fullerene functionalization via the photo induced nitrile imine-mediated tetrazole–ene cycloaddition (NITEC) is introduced.
Mechanical stimulation of single cells by reversible host-guest interactions in 3D microscaffolds
Publisher: American Association for the Advancement of Science (AAAS)
Date: 25-09-2020
Abstract: Using stimuli-responsive hydrogels, we 3D print composite microscaffolds to analyze mechanobiology on the single-cell level.
Spatially Controlled Surface Immobilization of Nonmodified Peptides
Publisher: Wiley
Date: 24-07-2013
High Performance Quantification of Complex High Resolution Polymer Mass Spectra
Publisher: American Chemical Society (ACS)
Date: 21-11-2018
An atom-efficient conjugation approach to well-defined block copolymers using RAFT chemistry and hetero Diels–Alder cycloaddition
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B718180A
Abstract: The tendency of electron-deficient dithioesters to undergo hetero Diels-Alder cycloadditions is successfully used to generate polymer conjugates between a RAFT-polymerized poly(styrene) and a diene-terminated poly(epsilon-caprolactone).
Green-light induced cycloadditions.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CC00340B
Abstract: We introduce a red-shifted tetrazole that is able to undergo efficient nitrile imine-mediated tetrazole-ene cycloaddition (NITEC) under blue and green light irradiation. We provide a detailed wavelength-dependent reactivity map, and employ a number of LEDs for high-conversion small molecule and polymer end-group modification.
End-Group Analysis of Polymers by Electrospray Ionization Mass Spectrometry: 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one Initiated Free-Radical Photopolymerization
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/CH02107
Abstract: End-group analysis of poly(methyl acrylate) and poly(dicyclohexyl itaconate) initiated by 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (MMMP) has been performed by electrospray ionization mass spectrometry (ESI-MS). MMMP has been found to fragment into two radicals that are near-equally capable of initiating free-radical polymerization processes. The present study indicates the occurrence of significant termination by disproportionation in the polymerization of methyl acrylate. Additionally, it has been demonstrated that dicyclohexyl itaconate undergoes termination by disproportionation almost exclusively.
Thermoresponsive Agarose Based Microparticles for Antibody Separation
Publisher: American Chemical Society (ACS)
Date: 15-12-2015
DOI: 10.1021/ACS.BIOMAC.5B01391
Abstract: We report the development of thermoresponsive 4-mercaptoethylpyridine (MEP)-based chromatographic microsphere based resins for antibody separation that show switchable release abilities by adsorbing immunoglobulins at 40 °C and releasing the proteins at 5 °C. The thermoswitchable release properties were introduced to the porous resins by the grafting of linear poly(N-isopropylacrylamide) (PNIPAM) chains synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, which were modified to possess MEP end functionalities. Adsorption of γ-globulins as a model antibody on the shortest PNIPAM-MEP (3 kDa) grafted microparticles display binding capacities of up to 20 g L(-1) at 40 °C and a significant decrease in binding capacity to less than 2.5 g L(-1) at 5 °C. By switching the temperature to 5 °C, the release of bound γ-globulins is shown to be as high as 90%. The effects of polymer chain length on the binding capacity are studied in detail and found to be critical as they influence the density of MEP functionalities on the particle surfaces.
Star polymer synthesis via λ-orthogonal photochemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC03848D
Abstract: λ-Orthogonal photo-induced ligation in two directions is introduced via a modular, light driven selective star shaped polymer formation.
A novel method for the measurement of degenerative chain transfer coefficients: proof of concept and experimental validation
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5PY02004B
Abstract: A novel method is presented to determine transfer coefficients in degenerative reversible addition fragmentation chain transfer (RAFT) polymerization from experimental dispersity data.
Unprecedented Bifunctional Chemistry of Bis(acyl)phosphane Oxides in Aqueous and Alcoholic Media
Publisher: Wiley
Date: 12-06-2019
Abstract: Tailor-made photoinitiators play an important role for efficient radical polymerisations in aqueous media, especially in hydrogel manufacturing. Bis(acyl)phosphane oxides (BAPOs) are among the most active initiators. Herein, we show that they display a remarkable photochemistry in aqueous and alcoholic media: Photolysis of BAPOs in the presence of water or alcohols provides a new delocalized π-radical, which does not participate in the polymerization. It either converts into a monoacylphosphane oxide acting as a secondary photoactive species or it works as a one-electron reducing agent. Upon the electron-transfer process, it again produces a dormant photoinitiator. We have established the structure and the chemistry of this π radical using steady-state and time-resolved (CIDEP) EPR together with ESI-MS, NMR spectroscopy, and DFT calculations. Our results show that bis(acyl)phosphane oxides act as bifunctional reagents when applied in aqueous and alcoholic media.
Fabrication of Conductive 3D Gold‐Containing Microstructures via Direct Laser Writing
Publisher: Wiley
Date: 08-03-2016
Abstract: 3D conductive microstructures containing gold are fabricated by simultaneous photopolymerization and photoreduction via direct laser writing. The photoresist employed consists of water-soluble polymers and a gold precursor. The fabricated microstructures show good conductivity and are successfully employed for 3D connections between gold pads.
Handbook of RAFT Polymerization
Publisher: Wiley
Date: 23-01-2008
Glass‐Transition‐, Melting‐, and Decomposition Temperatures of Tailored Polyacrylates and Polymethacrylates: General Trends and Structure–Property Relationships
Publisher: Wiley
Date: 05-05-2014
Individually Addressable Thermo‐ and Redox‐Responsive Block Copolymers by Combining Anionic Polymerization and RAFT Protocols
Publisher: Wiley
Date: 27-01-2014
Abstract: A novel diblock copolymer consisting of poly(vinylferrocene) (PVFc) and poly(N,N-diethylacrylamide) (PDEA) is synthesized via a combination of anionic and RAFT polymerization. The use of a novel route to hydroxyl-end-functionalized metallopolymers in anionic polymerization and subsequent esterification with a RAFT agent leads to a PVFc macro-CTA (M¯n = 3800 g mol(-1) Đ = 1.17). RAFT polymerization with DEA affords block copolymers as evidenced by (1) H NMR spectroscopy as well as size exclusion chromatography (6400 ≤ M¯n≤ 33700 g mol(-1) 1.31 ≤ Đ 1.28). Self-assembly of the hiphilic block copolymers in aqueous solution leads to micelles as shown via TEM. Importantly, the distinct thermo-responsive and redox-responsive character of the blocks is probed via dynamic light scattering and found to be in idually and repeatedly addressable.
Near Infrared Light Induced Radical Polymerization in Water
Publisher: Wiley
Date: 06-09-2022
Abstract: We introduce a gold nanorod (AuNR) driven methodology to induce free radical polymerization in water with near infrared light (800 nm). The process exploits photothermal conversion in AuNR and subsequent heat transfer to a radical initiator (here azobisisobutyronitrile) for primary radical generation. A broad range of reaction conditions were investigated, demonstrating control over molecular weight and reaction conversion of dimethylacrylamide polymers, using nuclear magnetic resonance spectroscopy. We underpin our experimental data with finite element simulation of the spatio‐temporal temperature profile surrounding the AuNR directly after femtosecond laser pulse excitation. Critically, we evidence that polymerization can be induced through biological tissues given the enhanced penetration depth of the near infrared light. We submit that the presented initiation mechanism in aqueous systems holds promise for radical polymerization in biological environments, including cells.
Switchable Macromolecular Systems – From Dynamic Chemistry to Self‐Healing
Publisher: Wiley
Date: 16-01-2012
All Eyes on Visible‐Light Peroxyoxalate Chemiluminescence Read‐Out Systems
Publisher: Wiley
Date: 19-11-2020
Abstract: Chemiluminescence (CL) reactions have been widely employed and explored over the past 50 years because they offer unique light emission upon a defined chemical stimulus. In this Minireview, we focus on peroxyoxalate (PO) compounds because they feature very high quantum yields tuneable over the entire visible spectrum, allowing for visible‐light detection by the naked eye without the necessity for expensive analytical instruments. Although analytical methods have been extensively described, PO‐CL read‐out is a strongly emerging field with le industrial potential. The state‐of‐the‐art PO‐CL detection read‐out systems for various key analytes is here explored. In particular, structural requirements, recent developments of PO‐CL read‐out probes and current limitations of selected ex les are detailed. Furthermore, innovative approaches and synthetic routes to push the boundaries of PO‐CL reactions into biological systems are highlighted. Underpinned by recent contributions, we share perspectives on embedding PO‐CL molecules into polymeric materials, which they consider the next step in designing high performance solid‐phase read‐out systems.
Polymer networks based on photo-caged diene dimerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8MH00951A
Abstract: The rapid self-dimerization of photochemically generated o -quinodimethanes is exploited for λ-orthogonal network formation.
Synthesis of polymers with phosphorus containing side chains via modular conjugation
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3PY00103B
Scope for Accessing the Chain Length Dependence of the Termination Rate Coefficient for Disparate Length Radicals in Acrylate Free Radical Polymerization
Publisher: Wiley
Date: 13-04-2007
Spin capturing with nitrones: Radical coupling reactions with concurrent introduction of mid-chain functionality
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B925390D
Abstract: Nitrones are demonstrated to efficiently mediate radical coupling reactions on the ex le of the conjugation of ATRP-made polymers, yielding macromolecules with distinct functional alkoxyamine centres in mid-chain locations of the chains.
A Novel Method for the Measurement of Chain Transfer to Monomer Constants in Styrene Homopolymerizations: The Pulsed Laser Rotating Reactor Assembly
Publisher: American Chemical Society (ACS)
Date: 28-03-2001
DOI: 10.1021/MA001871W
Blocks, Stars and Combs: Complex Macromolecular Architecture Polymers via Click Chemistry
Publisher: Wiley
Date: 20-10-2009
Amphiphilic block copolymers featuring a reversible hetero Diels-Alder linkage
Publisher: Royal Society of Chemistry (RSC)
Date: 03-06-2014
DOI: 10.1039/C4PY00644E
Wavelength Orthogonal Photodynamic Networks
Publisher: Wiley
Date: 15-03-2022
Abstract: The ability of light to remotely control the properties of soft matter materials in a dynamic fashion has fascinated material scientists and photochemists for decades. However, only recently has our ability to map photochemical reactivity in a finely wavelength resolved fashion allowed for different colors of light to independently control the material properties of polymer networks with high precision, driven by monochromatic irradiation enabling orthogonal reaction control. The current concept article highlights the progress in visible light‐induced photochemistry and explores how it has enabled the design of polymer networks with dynamically adjustable properties. We will explore current applications ranging from dynamic hydrogel design to the light‐driven adaptation of 3D printed structures on the macro‐ and micro‐scale. While the alternation of mechanical properties via remote control is largely reality for soft matter materials, we herein propose the next frontiers for adaptive properties, including remote switching between conductive and non‐conductive properties, hydrophobic and hydrophilic surfaces, fluorescent or non‐fluorescent, and cell adhesive vs. cell repellent properties.
Rapid UV Light‐Triggered Macromolecular Click Conjugations via the Use of o‐Quinodimethanes
Publisher: Wiley
Date: 05-04-2011
Abstract: Shining a light on click chemistry: The use of UV-radiation as trigger signal provides a facile means to obtain spatial and temporal control over polymer conjugation reactions in addition to providing a further means of achieving orthogonality in click transformations. In the current contribution, UV-radiation was employed to induce a highly efficient Diels-Alder conjugation of polymeric building blocks via the photo-induced in situ formation of highly reactive cis-dienes from a 2-methylbenzophenone precursor.
Ready access to end-functional polystyrenes via a combination of ARGET ATRP and thiol–ene chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5PY01048A
Abstract: Bromine end-groups of ATRP polystyrenes were converted into terminal alkene groups via a facile synthetic strategy. Subsequently, a light-induced radical thiol–ene reaction was employed for the functionalization of the terminal double bonds.
UV-induced photolysis of polyurethanes
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CC00124H
Abstract: Herein, we incorporate photosensitive ortho -Nitrobenzyl units into polyurethanes to achieve controllable photodegradability. We performed their photolysis in solution and thin films which can inform the design of degradable adhesives.
Enhanced Spin-capturing Polymerization and Radical Coupling Mediated by Cyclic Nitrones
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/CH12182
Abstract: A series of cyclic nitrones have been tested for their spin-trapping activity in the enhanced spin-capturing polymerization of styrene and in nitrone-mediated radical coupling reactions. rac-2-Isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-one was found to be the most efficient nitrone. The specific polystyrene macroradical addition rate to this nitrone was determined to be 8.0 × 103 L mol–1 s–1, which is by a factor of 10 higher than for previously studied compounds. Via enhanced spin-capturing polymerization, polymers in the range of oligomers to 30000 g mol–1 were obtained. A strong dependence of molecular weight on monomer conversion was observed, which can be explained by the high trapping rate. In nitrone-mediated radical coupling, almost ideal coupling of bromine-functional polymers was obtained and the successful introduction of the residual alkoxyamine functionality confirmed.
Dynamic Covalent Chemistry on Surfaces Employing Highly Reactive Cyclopentadienyl Moieties
Publisher: Wiley
Date: 23-08-2011
Spatially controlled surface immobilization of nucleophiles via trapping of photo-generated thioaldehydes
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SC50815C
Solvent Effects on kp in Organic Media?: Statement to the Response
Publisher: Wiley
Date: 26-08-2015
Abstract: A recent response on a publication from our team investigating solvent effects on propagation rate coefficients is commented. Among other issues, we point to the fact that the response interprets only a subset of the data provided in our original contribution.
Optimum Reaction Conditions for the Synthesis of Macromonomers Via the High‐Temperature Polymerization of Acrylates
Publisher: Wiley
Date: 21-10-2009
Abstract: Macromonomers are valuable synthetic building blocks: They can be copolymerized with low molecular weight monomers to generate brush‐like structures or serve as conjugation substrates in pericylic, metathesis, and thiolene reactions. Based on earlier reports on the facile high temperature formation of macromonomers from acrylates, a complex kinetic model is developed which accounts for the key reactions constituting the macromonomer formation process. On the basis of the kinetic model, the important rate coefficients governing acrylate polymerization (e.g., β ‐scission and termination rate coefficients of midchain radicals, backbiting and intramolecular chain transfer rate coefficients) as well as the reaction conditions (e.g., initial monomer concentration, reaction temperature, radical flux) are systematically varied and their influence on the synthetic success is critically evaluated. The systematic coefficient variation reveals that there exist optimum reaction conditions under which the high temperature macromonomers formation may be conducted with maximum success. The present study provides a concise summary of these conditions. magnified image
Living Free Radical Polymerization of Cyclodextrin Host‐Guest Complexes of Styrene via the Reversible Addition Fragmentation Chain Transfer (RAFT) Process in Aqueous Solution
Publisher: Wiley
Date: 18-05-2006
Depolymerization kinetics of di(4‐tert‐butyl cyclohexyl) itaconate and Mark‐Houwink‐Kuhn‐Sakurada parameters of di(4‐tert‐butyl cyclohexyl) itaconate and di‐n‐butyl itaconate
Publisher: Wiley
Date: 09-04-2007
DOI: 10.1002/POLA.21957
The Missing Piece: Concentration Dependence of Donor-Acceptor Stenhouse Adduct (DASA) Reactivity
Publisher: Wiley
Date: 05-05-2021
Abstract: Donor‐Acceptor Stenhouse Adducts (DASAs) are molecular photoswitches that reversibly isomerize from a linear to a cyclized form upon visible light irradiation. In the cyclized form, these molecules selectively react with a thiol in a thiol‐Michael addition. Driven by the complexity of the switching mechanism and chemical properties of DASAs, the effect of concentration (ranging from 1 to 5 mM DASA) on the thiol‐Michael addition was investigated. We find that the rate limiting step in the reaction is the photochemically induced DASA isomerization, as higher concentrations of thiol do not alter the rate at which the thiol‐Michael adduct (TMA) is formed. Moreover, the kinetics of the product formation were found to be more significantly affected by irradiation at higher concentrations. In two distinct scenarios, where either the concentration or the molar equivalence of the reaction partner was kept constant, the TMA was found to be more efficiently formed under irradiation at higher concentrations. These findings indicate that the DASA reactivity towards thiol‐Michael reactions appear to be equilibrium‐driven at lower concentrations and light‐driven at higher concentrations.
Macromolecular Superstructures: A Future Beyond Single Chain Nanoparticles
Publisher: Wiley
Date: 2020
From time dependent incorporation of molecular building blocks to application properties for inorganic and organic three-dimensional network polymers
Publisher: Research Square Platform LLC
Date: 12-11-2020
DOI: 10.21203/RS.3.RS-98270/V1
Abstract: The three-dimensional configurational arrangement of natural and synthetic network materials determines their application range. Control of the real time incorporation of each building block, hence, all functional groups is desired so that we can regulate macroscopic properties from the molecular level onwards. Here we interconnect kinetic Monte Carlo simulations from the field of chemical kinetics and molecular dynamic simulations from the field of physics. We visualize for (in)organic network material synthesis how the initial building blocks interact timewise and spatially, accounting for variations in inter- and intramolecular chemical reactivity, diffusivity, segmental compositions, branch/network point locations, and defects. We use the kinetic and three-dimensional structural information to construct structure-property relationships based on molecular descriptors such as the molecular pore size or dangling chain distribution, differentiating between ideal and non-ideal structural elements. The generic nature is illustrated by constructing such relationships for the synthesis of organosilica, epoxy-amine and Diels-Alder based networks.
Engineering Nitroxide Functional Surfaces Using Bioinspired Adhesion
Publisher: American Chemical Society (ACS)
Date: 14-02-2018
DOI: 10.1021/ACS.LANGMUIR.7B03755
Abstract: We pioneer a versatile surface modification strategy based on mussel-inspired oxidative catecholamine polymerization for the design of nitroxide-containing thin polymer films. A 3,4-dihydroxy-l-phenylalanine (l-DOPA) monomer equipped with a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-derived oxidation-labile hydroxylamine functional group is employed as a universal coating agent to generate polymer scaffolds with persistent radical character. Various types of materials including silicon, titanium, ceramic alumina, and inert poly(tetrafluoroethylene) (PTFE) were successfully coated with poly(DOPA-TEMPO) thin films in a one-step dip-coating procedure under aerobic, slightly alkaline (pH 8.5) conditions. Steadily growing polymer films (∼1.1 nm h
Sensitive Photoresists for Rapid Multiphoton 3D Laser Micro‐ and Nanoprinting
Publisher: Wiley
Date: 26-08-2020
The role of mid‐chain radicals in acrylate free radical polymerization: Branching and scission
Publisher: Wiley
Date: 27-10-2008
DOI: 10.1002/POLA.23071
Visible‐Light‐Degradable 3D Microstructures in Aqueous Environments
Publisher: Wiley
Date: 24-08-2022
Abstract: The additive manufacturing technique direct laser writing (DLW), also known as two‐photon laser lithography, is becoming increasingly established as a technique capable of fabricating functional 3D microstructures. Recently, there has been an increasing effort to impart microstructures fabricated using DLW with advanced functionalities by introducing responsive chemical entities into the underpinning photoresists. Herein, a novel photoresist based on the photochemistry of the bimane group is introduced that can be degraded upon exposure to very mild conditions, requiring only water and visible light (λ max = 415–435 nm) irradiation. The degradation of the microstructures is tracked and quantified using AFM measurements of their height. The influence of the writing parameters as well as the degradation conditions is investigated, unambiguously evidencing effective visible light degradation in aqueous environments. Finally, the utility of the photodegradable resist system is demonstrated by incorporating it into multimaterial 3D microstructures, serving as a model for future applications.
Regioselective photocycloaddition for light-stabilised dynamic materials design
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3PY00027C
Abstract: In this contribution, the influence of regioisomerism in covalent dynamic polymer materials is discussed and highlighted for light-stabilised dynamic materials, which motivated the development of a completely regioselective bonding/debonding system.
Efficient Surface Modification of Divinylbenzene Microspheres via a Combination of RAFT and Hetero Diels-Alder Chemistry
Publisher: Wiley
Date: 25-08-2008
Honeycomb structured porous films from amphiphilic block copolymers prepared via RAFT polymerization
Publisher: Elsevier BV
Date: 08-2007
Reversible addition fragmentation chain transfer polymerization of 3-[tris(trimethylsilyloxy) silyl] propyl methacrylate
Publisher: Elsevier BV
Date: 08-2003
Ambient Temperature Synthesis of Triblock Copolymers via Orthogonal Photochemically and Thermally Induced Modular Conjugation
Publisher: American Chemical Society (ACS)
Date: 31-05-2011
DOI: 10.1021/MA2010052
Electrospray Ionization Mass Spectrometry Investigation of Reversible Addition Fragmentation Chain Transfer Mediated Acrylate Polymerizations Initiated via 60Co γ-Irradiation: Mapping Reac
Publisher: American Chemical Society (ACS)
Date: 18-05-2007
DOI: 10.1021/MA0701484
Complex molecular architecture polymers via RAFT
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH03232
A Light-Activated Reaction Manifold
Publisher: American Chemical Society (ACS)
Date: 26-05-2016
DOI: 10.1021/JACS.6B01805
Abstract: We introduce an efficient reaction manifold where the rate of a thermally induced ligation can be controlled by a photonic field via two competing reaction channels. The effectiveness of the reaction manifold is evidenced by following the transformations of macromolecular chain termini via high-resolution mass spectrometry and subsequently by selective block copolymer formation. The light-controlled reaction manifold consists of a so-called o-quinodimethane species, a photocaged diene, that reacts in the presence of light with suitable enes in a Diels-Alder reaction and undergoes a transformation into imines with amines in the absence of light. The chemical selectivity of the manifold is controlled by the amount of ene present in the reaction and can be adjusted from 100% imine formation (0% photo product) to 5% imine formation (95% photo product). The reported light-controlled reaction manifold is highly attractive because a simple external field is used to switch the selectivity of specific reaction channels.
The incorporation of metal cations into polymer backbones: An important consideration in the interpretation of ESI-MS spectra
Publisher: Elsevier BV
Date: 10-2009
3D Scaffolds to Study Basic Cell Biology
Publisher: Wiley
Date: 21-02-2019
Abstract: Mimicking the properties of the extracellular matrix is crucial for developing in vitro models of the physiological microenvironment of living cells. Among other techniques, 3D direct laser writing (DLW) has emerged as a promising technology for realizing tailored 3D scaffolds for cell biology studies. Here, results based on DLW addressing basic biological issues, e.g., cell-force measurements and selective 3D cell spreading on functionalized structures are reviewed. Continuous future progress in DLW materials engineering and innovative approaches for scaffold fabrication will enable further applications of DLW in applied biomedical research and tissue engineering.
Photo‐Induced Click Chemistry for DNA Surface Structuring by Direct Laser Writing
Publisher: Wiley
Date: 27-03-2017
Abstract: Oligonucleotides containing photo-caged dienes were prepared and shown to react quantitatively in a light-induced Diels-Alder cycloaddition with functional maleimides in aqueous solution within minutes. Due to its high yield and fast rate, the reaction was exploited for DNA surface patterning with sub-micrometer resolution employing direct laser writing (DLW). Functional DNA arrays were written by direct laser writing (DLW) in variable patterns, which were further encoded with fluorophores and proteins through DNA directed immobilization. This mild and efficient light-driven platform technology holds promise for the fabrication of complex bioarrays with sub-micron resolution.
Australian European Self-Assembly through Macromolecular Interactions
Publisher: Wiley
Date: 10-2016
2D Fabrication of Tunable Responsive Interpenetrating Polymer Networks from a Single Photoresist
Publisher: Wiley
Date: 15-09-2020
On the macrocyclization selectivity of meta-substituted diamines and dialdehydes: towards macrocycles with tunable functional peripheries
Publisher: Springer Science and Business Media LLC
Date: 25-06-2019
Two- and three-photon processes in photoinitiators for 3D laser printing
Publisher: Research Square Platform LLC
Date: 05-07-2022
DOI: 10.21203/RS.3.RS-1797484/V1
Abstract: The performance of a photoinitiator is key to control efficiency and resolution in 3D laser nanoprinting. Upon light absorption, a cascade of competing excited states and photoreactions leads to the radical formation that initiates free radical polymerization. Here we investigate 7-diethylamino-3-thenoylcoumarin (DETC), one of the most efficient photoinitiators for two-photon polymerization (TPP). Depending on the presence of a co-initiator, DETC causes radical generation either with two-photon or with a unique three-photon excitation, but the mechanism for these processes is not well understood. Here we show that the unique three-photon based radical formation of DETC in the absence of a co-initiator results from the excitation of special highly excited triplet states followed by multiple bond scission possibilities generating radicals. In contrast, photoinitiation in the presence of a co-initiator proceeds via intermolecular electron transfer or hydrogen atom transfer after the photosensitization of the photoinitiator to the lowest triplet excited state. Our quantum mechanical calculations explain the different pathways for the multiphoton activation mechanism of DETC and its radical formation, which enables the rational design of efficient photoinitiators to increase the speed and sensitivity of 3D laser nanoprinting.
Access to Three‐Arm Star Block Copolymers by a Consecutive Combination of the Copper(I)‐Catalyzed Azide–Alkyne Cycloaddition and the RAFT Hetero Diels–Alder Concept
Publisher: Wiley
Date: 07-2008
Abstract: Three‐arm star block copolymers have been synthesized from linear polystyrene (PS) and poly( ε ‐caprolactone) (PCL) building blocks. Through the use of an α ‐diene‐ ω ‐alkyne functionalized PCL, the PS‐ b ‐PCL stars have been synthesized via either forming the PS‐ b ‐PCL arms first with the hetero Diels–Alder (HDA) cycloaddition and their subsequent coupling to a triazide coupling agent through a copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) (arm‐first) or via forming the basic star structure first through the CuAAC of the coupling agent and the PCL, with the diblock stars achieved by the subsequent HDA cycloaddition with the PS (core‐first). The use of the two consecutive reactions has facilitated high conversions and a good control over the multiple reaction sites. In both ex les, the CuAAC proceeded to quantitative conversion whereas the HDA cycloaddition proceeded to 94% conversion in the arm‐first approach and 81% in the core‐first approach. magnified image
Challenges and Opportunities in 3D Laser Printing Based on (1 + 1)-Photon Absorption
Publisher: American Chemical Society (ACS)
Date: 14-12-2022
Mild and Efficient Modular Synthesis of Poly(acrylonitrile-co-butadiene) Block and Miktoarm Star Copolymer Architectures
Publisher: American Chemical Society (ACS)
Date: 27-12-2012
DOI: 10.1021/MA302017C
Shell-Cross-Linked Micelles Containing Cationic Polymers Synthesized via the RAFT Process: Toward a More Biocompatible Gene Delivery System
Publisher: American Chemical Society (ACS)
Date: 11-08-2007
DOI: 10.1021/BM070370G
Abstract: Block copolymers poly(2-(dimethylamino) ethyl methacrylate)-b-poly(polyethylene glycol methacrylate) (PDMAEMA-b-P(PEGMA)) were prepared via reversible addition fragmentation chain transfer polymerization (RAFT). The polymerization was found to proceed with the expected living behavior resulting in block copolymers with varying block sizes of low polydispersity (PDI <1.3). The resulting block copolymer was self-assembled in an aqueous environment, leading to the formation of pH-responsive micelles. Further stabilization of the micellar system was performed in water using ethylene glycol dimethacrylate and the RAFT process to cross-link the shell. The cross-linked micelle was found to have properties significantly different from those of the uncross-linked block copolymer micelle. While a distinct critical micelle concentration (CMC) was observed using block copolymers, the CMC was absent in the cross-linked system. In addition, a better stability against disintegration was observed when altering the ionic strength such as the absence of changes of the hydrodynamic diameter with increasing NaCl concentration. Both cross-linked and uncross-linked micelles displayed good binding ability for genes. However, the cross-linked system exhibited a slightly superior tendency to bind oligonucleotides. Cytotoxicity tests confirmed a significant improvement of the biocompatibility of the synthesized cross-linked micelle compared to that of the highly toxic PDMAEMA. The cross-linked micelles were taken up by cells without causing any signs of cell damage, while the PDMAEMA homopolymer clearly led to cell death.
STED-inspired Laser Lithography Based on Spirothiopyran Chromophores
Publisher: OSA
Date: 2018
Two Colour Photoflow Chemistry for Macromolecular Design
Publisher: Wiley
Date: 08-06-2020
Abstract: We report a photochemical flow setup that exploits λ‐orthogonal reactions using two different colours of light (λ 1 =350 nm and λ 2 =410 nm) in sequential on‐line irradiation steps. Critically, both photochemically reactive units (a visible‐light reactive chalcone and a UV‐activated photo‐caged diene) are present in the reaction mixture. We demonstrate the power of two colour photoflow by the wavelength‐selective end group modification of photo‐caged polymer end groups and the subsequent polymer ring closure driven by a [2+2] cycloaddition. Importantly, we evidence that the high energy gate does not induce the visible light reaction of the chalcone, which attests the true λ‐orthogonal nature of the flow reaction system. For the first time, this study opens the realm of photoflow reactions to λ‐orthogonal photochemistry.
Remarkable Solvent Effects of Oxygen- and Sulfur-Containing Compounds on the Propagation Rate of Methyl Methacrylate
Publisher: Walter de Gruyter GmbH
Date: 03-2005
DOI: 10.1524/ZPCH.219.3.267.59184
Abstract: The propagation kinetics of methyl methacrylate (MMA) in the presence of a number of oxygen- and sulfur-containing compounds have been investigated. Solvents used were 2-methyl-1,3-dioxepane (MDOP), 2,6-dithiaheptane (DTHP) and 1,5-dithiacyclooctane (DTCO). In the presence of DTHP and DTCO, the propagation rate coefficient, k p , of MMA was found to be 25% to 100% higher compared to bulk polymerisations under the same conditions. The significant increase of k p was explained by electron donation from the sulfur-containing solvents, which increased the reactivity of the macroradicals. MDOP had no observable effect on k p . The solvent influence on polymer tacticity was also studied using both 1 H and 13 C NMR spectroscopy. No significant influence of the solvent on polymer tacticity was found.
Star and miktoarm star block (co)polymers viaself-assembly of ATRP generated polymer segments featuring Hamilton wedge and cyanuric acid binding motifs
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0PY00395F
Abstract: The self-assembly of well-defined ATRP prepared polymers with terminal and mid-chain Hamilton wedge as well as cyanuric acid binding motifs is demonstrated to be an efficient avenue to star and miktoarm star block copolymers.
Living characteristics of the free-radical ring-closing polymerization of diallyldimethylammonium chloride
Publisher: Elsevier BV
Date: 2011
Adaptable Hetero Diels–Alder Networks for Fast Self‐Healing under Mild Conditions
Publisher: Wiley
Date: 21-03-2014
Visible Light-Induced Ligation via o-Quinodimethane Thioethers.
Publisher: American Chemical Society (ACS)
Date: 23-08-2018
DOI: 10.1021/JACS.8B08343
Abstract: We introduce a photocaged diene system ( o-quinodimethane thioethers) based on o-methylbenzaldehydes ( o-MBAs) that can be activated with visible light. The pioneered system is accessible in a single step from commercially available starting materials in excellent yields. Variable synthetic handles can be attached to the photocaged diene, often without elaborate protecting group chemistry. Full conversion of various o-methylbenzaldehydes to the Diels-Alder adduct is achieved in the presence of maleimides under catalyst-free conditions triggered by visible light irradiation with LEDs under flow conditions. Unlike the previously reported UV-induced ligation of o-quinodimethanes, the reaction can be conducted both in organic solvents and in aqueous solution. We further demonstrate the ability of the photocaged dienes to ligate two polymer blocks by visible light. The [4+2] nature of the reaction makes it a powerful orthogonal ligation platform.
In Situ Formation of Protein–Polymer Conjugates through Reversible Addition Fragmentation Chain Transfer Polymerization
Publisher: Wiley
Date: 12-04-2007
Probing mechanistic features of conventional, catalytic and living free radical polymerizations using soft ionization mass spectrometric techniques
Publisher: Elsevier BV
Date: 10-2004
Facile conversion of RAFT polymers into hydroxyl functional polymers: a detailed investigation of variable monomer and RAFT agent combinations
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B9PY00273A
Design Criteria for Star Polymer Formation Processes via Living Free Radical Polymerization
Publisher: American Chemical Society (ACS)
Date: 19-08-2006
DOI: 10.1021/MA060964W
Near‐Infrared Photoinduced Reactions Assisted by Upconverting Nanoparticles
Publisher: Wiley
Date: 10-04-2017
Abstract: The majority of photoreactions reported in the literature rely on wavelengths within the UV and-to a lesser extent-visible regime for activation, either by directly triggering the reaction or by photocatalysis. However, photoreactions induced by near-infrared (NIR) light are highly attractive for biomedical applications as NIR light can penetrate deeper into tissue and causes less damage to photosensitive biological systems. Recently, upconverting nanoparticles (UCNPs) have been employed by us and others to assist NIR photoinduced reactions. UCNPs convert NIR light to UV or visible light, which can trigger photoreactions of conventional UV or visible-light-sensitive compounds. In the current Concept article, we introduce the fundamentals of UCNP-assisted photochemistry and highlight selected future applications and innovative potential for the field.
Controlling thermal reactivity with different colors of light
Publisher: Springer Science and Business Media LLC
Date: 30-11-2017
DOI: 10.1038/S41467-017-02022-0
Abstract: The ability to switch between thermally and photochemically activated reaction channels with an external stimulus constitutes a key frontier within the realm of chemical reaction control. Here, we demonstrate that the reactivity of triazolinediones, powerful coupling agents in biomedical and polymer research, can be effectively modulated by an external photonic field. Specifically, we show that their visible light-induced photopolymerization leads to a quantitative photodeactivation, thereby providing a well-defined off-switch of their thermal reactivity. Based on this photodeactivation, we pioneer a reaction manifold using light as a gate to switch between a UV-induced Diels–Alder reaction with photocaged dienes and a thermal addition reaction with alkenes. Critically, the modulation of the reactivity by light is reversible and the in idually addressable reaction pathways can be repeatedly accessed. Our approach thus enables a step change in photochemically controlled reactivity, not only in small molecule ligations, yet importantly in controlled surface and photoresist design.
Polymer‐Fullerene Network Formation via Light‐Induced Crosslinking
Publisher: Wiley
Date: 23-06-2016
Abstract: A facile and efficient methodology for the formation of polymer-fullerene networks via a light-induced reaction is reported. The photochemical crosslinking is based on a nitrile imine-mediated tetrazole-ene cycloaddition reaction, which proceeds catalyst-free under UV-light irradiation (λmax = 320 nm) at ambient temperature. A tetrazole-functionalized polymer (Mn = 6500 g mol(-1) , Ð = 1.3) and fullerene C60 are employed for the formation of the hybrid networks. The tetrazole-functionalized polymer as well as the fullerene-containing networks are carefully characterized by NMR spectrometry, size exclusion chromatography, infrared spectroscopy, and elemental analysis. Furthermore, thermal analysis of the fullerene networks and their precursors is carried out. The current contribution thus induces an efficient platform technology for fullerene-based network formation.
Access to Disparate Soft Matter Materials by Curing with Two Colors of Light
Publisher: Wiley
Date: 07-01-2019
Abstract: A platform technology for multimaterial photoresists that can be orthogonally cured by disparate colors of light is introduced. The resist's photochemistry is designed such that one wavelength selectively activates the crosslinking of one set of macromolecules, while a different wavelength initiates network formation of a different set of chains. Each wavelength is thus highly selective towards a specific photoligation reaction within the resist. Critically, the shorter wavelength does not induce ligation of the longer wavelength selective species within the same resist mixture, defined as "wavelength orthogonality." Uniquely, this dual-color addressable resist system allows generating spatially resolved soft matter materials by simply selecting the curing wavelength, thus constituting a wavelength-orthogonal multimaterial resist with applications ranging from coatings to 3D additive manufacturing of multimaterial architectures.
A Detailed investigation of the experimental conditions for the reversible addition fragmentation chain transfer‐mediated copolymerization of acrylonitrile and butadiene
Publisher: Wiley
Date: 28-10-2011
DOI: 10.1002/POLA.25033
Photo‐Patterning of Non‐Fouling Polymers and Biomolecules on Paper
Publisher: Wiley
Date: 09-04-2014
Abstract: Functional cellulose substrates with tetrazole moieties are generated to serve as universal platforms for the spatio-temporal immobilization of synthetic ultra-low fouling polymer brushes and protein species via a nitrile imine-mediated tetrazole-ene cycloaddition (NITEC)-based protocol. Poly(carboxybetaine acrylamide) brushes are grafted from initiators photo-patterned by NITEC utilizing single electron transfer living radical polymerization. Streptavidin is photo-immobilized with remarkable efficiency, opening the possibility to generate new materials for biomedical and biosensing applications.
Maleimide-functionalized poly(2-ethyl-2-oxazoline): synthesis and reactivity
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6PY00033A
Abstract: Poly(2-ethyl-2-oxazoline)s end-functionalized with a maleimide moiety were prepared from azide-terminated PEtOx x -N 3 via copper-catalyzed azide–alkyne cycloaddition (CuAAC) with an alkyne-bearing maleimide (MI).
Access to the β-scission rate coefficient in acrylate radical polymerization by careful scanning of pulse laser frequencies at elevated temperature
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RE00171E
Abstract: A novel method to estimate the β-scission rate coefficient in acrylate radical polymerization is presented.
Entropy driven chain effects on ligation chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4SC02908A
Abstract: Entropic chain effects on dynamic bonding reactions are shown to enable the tuning of reaction equilibria not only by changing the mass of the reactants, but also by merely altering the building block side chain structure and thus the intrinsic stiffness. The findings enable a step change for the design of on-demand bonding systems and reversible ligation chemistry in general.
Modular functionalization and hydrogel formation via red-shifted and self-reporting [2+2] cycloadditions
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0CC07429B
Abstract: We introduce a modular photodynamic covalent crosslinker, named qStyPy, with an increased water-solubility that undergoes [2+2] cycloadditions upon irradiation with 470 nm and directly self-reports on its cycloadduct formation.
Fully independent photochemical reactivity in one molecule
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC04781F
Abstract: We introduce a chemically λ -orthogonal bichromophore triggered simply by different colours of light, enabling two different photochemical reactions in one molecule.
Electrochemical Stimulation of Water–Oil Interfaces by Nonionic–Cationic Block Copolymer Systems
Publisher: American Chemical Society (ACS)
Date: 23-12-2020
Solvent and oxygen effects on the free radical polymerization of 6-O-vinyladipoyl-d-glucopyranose
Publisher: Elsevier BV
Date: 04-2005
Direct Visualization of Homogeneous Chemical Distribution in Functional Polyradical Microspheres
Publisher: Wiley
Date: 26-02-2023
Abstract: It is demonstrated that the postfunctionalization of solid polymeric microspheres can generate fully and throughout functionalized materials, contrary to the expectation that core–shell structures are generated. The full functionalization is illustrated on the ex le of photochemically generated microspheres, which are subsequently transformed into polyradical systems. Given the all‐organic nature of the functionalized microspheres, characterization methods with high analytical sensitivity and spatial resolution are pioneered by directly visualizing the inner chemical distribution of the postfunctionalized microspheres based on characteristic electron energy loss signals in transmission electron microscopy (TEM). Specifically, ultrasonic ultramicrotomy is combined successfully with electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) during TEM. These findings open a key avenue for analyzing all‐organic low‐contrast soft‐matter material structures, while the specifically investigated system concomitantly holds promise as an all‐radical solid‐state functional material.
Photo-induced sequence defined macromolecules via hetero bifunctional synthons
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CC08756A
Abstract: We report the first photochemical protocol for the generation of sequence defined macromolecules employing two hetero bifunctional photoreactive synthons, exploiting the orthogonal nature of photochemical – via the use of caged dienes – and thermally driven ligation protocols.
Termination Rate Coefficient of Dimethyl Itaconate: Comparison of Modeling and Experimental Results
Publisher: American Chemical Society (ACS)
Date: 02-2002
DOI: 10.1021/MA011535V
Acrylamide-Based Copolymers Bearing Photoreleasable Thiols for Subsequent Thiol–Ene Functionalization
Publisher: American Chemical Society (ACS)
Date: 08-02-2012
DOI: 10.1021/MA202670D
Acrylonitrile‐Butadiene Rubber (NBR) Prepared via Living/Controlled Radical Polymerization (RAFT)
Publisher: Wiley
Date: 06-09-2010
Abstract: In the current work we present results on the controlled/living radical copolymerization of acrylonitrile (AN) and 1,3-butadiene (BD) via reversible addition fragmentation chain transfer (RAFT) polymerization techniques. For the first time, a solution polymerization process for the synthesis of nitrile butadiene rubber (NBR) via the use of dithioacetate and trithiocarbonate RAFT agents is described. It is demonstrated that the number average molar mass, $\\overline M _{\\rm n} $, of the NBR can be varied between a few thousand and 60 000 g · mol(-1) with polydispersities between 1.2 and 2.0 (depending on the monomer to polymer conversion). Excellent agreement between the experimentally observed and the theoretically expected molar masses is found. Detailed information on the structure of the synthesized polymers is obtained by variable analytical techniques such as infrared spectroscopy (IR), nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry, and electrospray ionization-mass spectrometry (ESI-MS).
A Photochemical Ligation System Enabling Solid‐Phase Chemiluminescence Read‐Out
Publisher: Wiley
Date: 09-07-2019
Abstract: The peroxyoxalate chemiluminescence (PO-CL) reaction is among the most powerful and versatile techniques for the detection of hydrogen peroxide (H
Oxidative polymerization of terthiophene and a substituted thiophene monomer in metal-organic framework thin films
Publisher: Elsevier BV
Date: 12-2018
Passerini Multicomponent Reactions Enabling Self-Reporting Photosensitive Tetrazole Polymers
Publisher: American Chemical Society (ACS)
Date: 03-09-2021
DOI: 10.1021/ACSMACROLETT.1C00280
Abstract: We introduce the synthesis of photosensitive tetrazole monomers via Passerini multicomponent reactions (MCRs). We exploit the MCR's tolerance toward various functional groups under mild, catalyst-free conditions in a one-pot reaction setup to generate tetrazole-containing monomers featuring a methacrylic moiety, which enables their subsequent reversible addition-fragmentation chain transfer (RAFT) polymerization. By employing tetrazoles with either a 4-methoxy phenyl or a pyrene substituent, further modifications of the polymers in a wavelength-orthogonal, self-reporting fashion upon irradiation with either UV or visible light become possible.
Lithium–air battery cathode modification via an unconventional thermal method employing borax
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA05685G
Abstract: A novel approach for the preparation of porous carbon materials and its successful application for the carbon electrode of lithium air batteries is demonstrated.
A Simple and Versatile Pathway for the Synthesis of Visible Light Photoreactive Nanoparticles
Publisher: Wiley
Date: 19-04-2018
Interrupted CuAAC Ligation: An Efficient Approach to Fluorescence Labeled Three-Armed Mikto Star Polymers
Publisher: American Chemical Society (ACS)
Date: 29-03-2018
Modular design of glyco-microspheres via mild pericyclic reactions and their quantitative analysis
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY20369C
Initiator efficiency of 2,2′‐azobis(isobutyronitrile) in bulk dodecyl acrylate free‐radical polymerizations over a wide conversion and molecular weight range
Publisher: Wiley
Date: 09-09-2004
DOI: 10.1002/POLA.20322
Detailed investigation of the propagation rate of urethane acrylates
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B9PY00352E
Abstract: Propagation rate coefficients are provided—for the first time—for an entire class of urethane moieties containing acrylates, which display an extremely high propagation rate.
Making Light Work of Material Design
Publisher: Wiley
Date: 24-06-2019
Wavelength Dependence of Light-Induced Cycloadditions.
Publisher: American Chemical Society (ACS)
Date: 25-10-2017
DOI: 10.1021/JACS.7B08047
Abstract: The wavelength-dependent conversion of two rapid photoinduced ligation reactions, i.e., the light activation of o-methylbenzaldehydes, leading to the formation of reactive o-quinodimethanes (photoenols), and the photolysis of 2,5-diphenyltetrazoles, affording highly reactive nitrile imines, is probed via a monochromatic wavelength scan at constant photon count. The transient species are trapped by cycloaddition with N-ethylmaleimide, and the reactions are traced by high resolution mass spectrometry and nuclear magnetic resonance spectroscopy. The resulting action plots are assessed in the context of Beer-Lambert's law and provide combined with time-dependent density functional theory and multireference calculations an in-depth understanding of the underpinning mechanistic processes, including conical intersections. The π → π* transition of the carbonyl group of the o-methylbenzaldehyde correlates with a highly efficient conversion to the cycloadduct, showing no significant wavelength dependence, while conversion following the n → π* transition proceeds markedly less efficient at longer wavelengths. The influence of absorbance and reactivity has critical consequences for an effective reaction design: At high concentrations of o-methylbenzaldehydes (c = 8 mmol L
Reversible addition–fragmentation chain‐transfer polymerization: Unambiguous end‐group assignment via electrospray ionization mass spectrometry
Publisher: Wiley
Date: 03-10-2002
DOI: 10.1002/POLA.10500
DNA‐Polymer‐Nanostrukturen durch RAFT‐Polymerisation und polymerisationsinduzierte Selbstassemblierung
Publisher: Wiley
Date: 17-06-2020
Kinetics of Strain-Activated Intramolecular Diels-Alder Reactions Between Furan and Bicyclopropylidene as well as Methylenecyclopropane Moieties
Publisher: Wiley
Date: 1998
DOI: 10.1002/(SICI)1099-0690(199801)1998:1<107::AID-EJOC107>3.0.CO;2-Q
Access to Chain Length Dependent Termination Rate Coefficients of Methyl Acrylate via Reversible Addition−Fragmentation Chain Transfer Polymerization
Publisher: American Chemical Society (ACS)
Date: 25-02-2005
DOI: 10.1021/MA047476D
Molecular Switch for Sub-Diffraction Laser Lithography by Photoenol Intermediate-State Cis–Trans Isomerization
Publisher: American Chemical Society (ACS)
Date: 08-06-2017
Abstract: Recent developments in stimulated-emission depletion (STED) microscopy have led to a step change in the achievable resolution and allowed breaking the diffraction limit by large factors. The core principle is based on a reversible molecular switch, allowing for light-triggered activation and deactivation in combination with a laser focus that incorporates a point or line of zero intensity. In the past years, the concept has been transferred from microscopy to maskless laser lithography, namely direct laser writing (DLW), in order to overcome the diffraction limit for optical lithography. Herein, we propose and experimentally introduce a system that realizes such a molecular switch for lithography. Specifically, the population of intermediate-state photoenol isomers of α-methyl benzaldehydes generated by two-photon absorption at 700 nm fundamental wavelength can be reversibly depleted by simultaneous irradiation at 440 nm, suppressing the subsequent Diels-Alder cycloaddition reaction which constitutes the chemical core of the writing process. We demonstrate the potential of the proposed mechanism for STED-inspired DLW by covalently functionalizing the surface of glass substrates via the photoenol-driven STED-inspired process exploiting reversible photoenol activation with a polymerization initiator. Subsequently, macromolecules are grown from the functionalized areas and the spatially coded glass slides are characterized by atomic-force microscopy. Our approach allows lines with a full-width-at-half-maximum of down to 60 nm and line gratings with a lateral resolution of 100 nm to be written, both surpassing the diffraction limit.
Synthesis of core-shell poly(divinylbenzene) microspheres via reversible addition fragmentation chain transfer graft polymerization of styrene
Publisher: Wiley
Date: 07-09-2004
DOI: 10.1002/POLA.20328
Fluorescent and Catalytically Active Single Chain Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 10-11-2022
Characterization of human-like menstruation in the spiny mouse: comparative studies with the human and induced mouse model.
Publisher: Oxford University Press (OUP)
Date: 19-07-2018
Abstract: Is the newly discovered menstruating rodent, the spiny mouse, a valid model for studying endometrial morphology and menstruation? Our study is the first to demonstrate a primate-like pattern of natural menstruation in a rodent, with decidualization, spiral arteriole remodeling and piece-meal endometrial shedding. The spiny mouse has a naturally occurring menstrual cycle. This unique feature has the potential to reduce the heavy reliance on primates and provide a more appropriate small animal model for menstrual physiology research. This study compares morphological changes in the endometrium during early, mid and late menstruation of the spiny mouse (n = 39), human (n = 9) and the induced mouse model of menstruation (n = 17). We assessed tissue morphology with hematoxylin and eosin and erythrocyte patterns with Mallory's trichrome. We conducted staining for neutrophil gelatinase associated lipocalin (NGAL), cytokeratin and interleukin-11 (IL-11) in all species. We used double immunofluorescence staining for vascular endothelial growth factor and alpha-smooth muscle actin to detect vasculature remodeling and western immunoblot to detect interleukin-8 (IL-8) and macrophage migration inhibitory factor (MIF) in the menstrual fluid of spiny mice. Menstruation occurs in the spiny mouse over a 72-h period, with heaviest menstrual breakdown occurring 24 h after initial observation of red blood cells in the vaginal cytology. During menstruation, the endometrium of the spiny mouse appeared to resemble human menstrual shedding with focal epithelial breakdown observed in conjunction with lysis of underlying stroma and detection of IL-8 and MIF in menstrual fluid. The mouse exhibits extensive decidualization prior to induced menses, with transformation of the entire uterine horn and cytokeratin expression absent until initiation of repair. Decidualization occurred spontaneously and was less marked in the spiny mouse, where epithelial integrity remained intact. In all species, the decidua was positive for IL-11 secretion and neutrophil recruitment was similar in each. Spiral arteriole formation was confirmed in the spiny mouse. N/A. This is a descriptive study comparing primarily morphological traits between the spiny mouse, the mouse and the human. Reagents specific to the spiny mouse were limited and resources for global use of this novel species are few. Our work supports the spiny mouse as a viable model, sharing many attributes of physiological menstruation with humans. The strength of a natural as opposed to an artificial model is validated through the striking similarities observed between the spiny mouse and human in uterine breakdown. The spiny mouse may be highly useful in large-scale investigations of menstruation and menstrual disorders. N.B. and S.R. are each recipients of a Research Training Program scholarship supported by Monash University. This work was supported by the Victorian Government Operational Infrastructure and laboratory funds to H.D. The authors declare no competing interests.
Single‐Chain Self‐Folding of Synthetic Polymers Induced by Metal–Ligand Complexation
Publisher: Wiley
Date: 07-10-2013
Abstract: The controlled folding of a single polymer chain is for the first time realized by metal- complexation. α,ω-Bromine functional linear polymers are prepared via activators regenerated by electron transfer (ARGET) ATRP (M¯n,SEC = 5900 g mol(-1) , Đ = 1.07 and 12 000 g mol(-1) , Đ = 1.06) and the end groups of the polymers are subsequently converted to azide functionalities. A copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction is carried out in the presence of a novel triphenylphosphine ligand and the polymers to afford homotelechelic bis-triphenylphosphine polymeric-macroligands (MLs) (M¯n,SEC = 6600 g mol(-1) , Đ = 1.07, and 12 800 g mol(-1) , Đ = 1.06). Single-chain metal complexes (SCMCs) are formed in the presence of Pd(II) ions in highly diluted solution at ambient temperature. The results derived via (1) H and (31) P{(1) H} NMR experiments, SEC, and DLS unambiguously evidence the efficient formation of SCMCs via metal ligand complexation.
Specialising Simulator Generators for High-Performance Monte-Carlo Methods
Publisher: Springer Berlin Heidelberg
Date: 2008
Orange-Light-Induced Photochemistry Gated by pH and Confined Environments
Publisher: American Chemical Society (ACS)
Date: 02-04-2022
DOI: 10.1021/JACS.2C00156
Abstract: We introduce a new photochemically active compound, i.e., pyridinepyrene (PyPy), entailing a pH-active moiety that effects a significant halochromic shift into orange-light (λ = 590 nm) activatable photoreactivity while concomitantly exerting control over its reaction pathways. With blue light (λ = 450 nm) in neutral to basic pH, a [2 + 2] photocycloaddition can be triggered to form a cyclobutene ring in a reversible fashion. If the pH is decreased to acidic conditions, resulting in a halochromic absorption shift, photocycloaddition on the small-molecule level is blocked due to repulsive interactions and exclusive
Photo-induced chemistry for the design of oligonucleotide conjugates and surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TB02207J
Abstract: A photocaged diene is introduced at the 5′-end of oligonucleotides using the H-phosphonate approach and subsequently employed for the light-induced conjugation to a protein and the spatially controlled immobilization onto surfaces.
Universal mass spectrometric analysis of poly(ionic liquid)s
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6SC01347C
Abstract: We introduce a universal tool for the mass spectrometric analysis of a wide range of various types of poly(ionic liquids).
Controlled Cell Adhesion on Poly(dopamine) Interfaces Photopatterned with Non‐Fouling Brushes
Publisher: Wiley
Date: 03-09-2013
Abstract: Bioinspired poly(dopamine) (PDA) films are merged with antifouling poly(MeOEGMA) brushes utilizing a nitrile imine-mediated tetrazole-ene cycloaddition (NITEC)-based phototriggered surface encoding protocol. The antifouling brushes were photopatterned on PDA surfaces, leading cells to form confluent layers in the non-irradiated sections, while no adhesion occurred on the brushes resulting in a remarkably precise cell pattern. The presented strategy paves the way for the design of tailor-made patterned cell interfaces.
Mapping Formation Pathways and End Group Patterns of Stimuli-Responsive Polymer Systems via High-Resolution Electrospray Ionization Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 26-07-2007
DOI: 10.1021/BM700526J
Abstract: "Smart" polymers and polymer-protein conjugates find a vast array of biomedical applications. Ambient temperature reversible addition fragmentation chain transfer (RAFT) polymerizations conducted in an aqueous environment are a favorable method of choice for the synthesis of these materials however, information regarding the initiation mechanisms behind these polymerizations-and thus the critical polymer end groups-is lacking. In the current study, high-resolution soft ionization mass spectrometry techniques were used to map the product species generated during ambient temperature gamma-radiation induced RAFT polymerizations of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) in aqueous media, allowing the generated end groups to be unambiguously established. It was found that trithiocarbonate and *R radicals produced from the radiolysis of the RAFT agent, *OH and *OOH radicals produced from the radiolysis of water, and *H radicals produced from the radiolysis of water, RAFT agent, or monomer were capable of initiating polymerizations and thus contribute toward the generated chain ends. Additionally, thiol terminated chains were formed via degradation of trithiocarbonate end groups. The current study is the first to provide comprehensive mapping of the formation pathways and end group patterns of stimuli-responsive polymers, thus allowing the design and implementation of these materials to proceed in a more tailored fashion.
Phase Inversion Membranes from Amphiphilic Diblock Terpolymers
Publisher: Wiley
Date: 16-04-2015
Hyperbranched polymers as scaffolds for multifunctional reversible addition-fragmentation chain-transfer agents
Publisher: Wiley
Date: 23-10-2003
DOI: 10.1002/POLA.10976
Polybutadiene Functionalization via an Efficient Avenue
Publisher: American Chemical Society (ACS)
Date: 23-09-2016
DOI: 10.1021/ACSMACROLETT.6B00679
Abstract: We introduce a facile and quantitative postpolymerization functionalization methodology for 1,4-polybutadienes, allowing us to decorate their pendent alkene functionalities with bromine and alkoxyether motifs carrying an array of functional groups ranging from tetrazoles to pyrenes. Specifically, the approach makes use of a mild, metal-free, electrophilic cascade reaction employing
Polyphthalaldehyde-block-polystyrene as a nanochannel template
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TB00491D
Green light triggered [2+2] cycloaddition of halochromic styrylquinoxaline—controlling photoreactivity by pH
Publisher: Springer Science and Business Media LLC
Date: 21-08-2020
DOI: 10.1038/S41467-020-18057-9
Abstract: Photochemical reactions are a powerful tool in (bio)materials design due to the spatial and temporal control light can provide. To extend their applications in biological setting, the use of low-energy, long wavelength light with high penetration propertiesis required. Further regulation of the photochemical process by additional stimuli, such as pH, will open the door for construction of highly regulated systems in nanotechnology- and biology-driven applications. Here we report the green light induced [2+2] cycloaddition of a halochromic system based on a styrylquinoxaline moiety, which allows for its photo-reactivity to be switched on and off by adjusting the pH of the system. Critically, the [2+2] photocycloaddition can be activated by green light (λ up to 550 nm), which is the longest wavelength employed to date in catalyst-free photocycloadditions in solution. Importantly, the pH-dependence of the photo-reactivity was mapped by constant photon action plots. The action plots further indicate that the choice of solvent strongly impacts the system’s photo-reactivity. Indeed, higher conversion and longer activation wavelengths were observed in water compared to acetonitrile under identical reaction conditions. The wider applicability of the system was demonstrated in the crosslinking of an 8-arm PEG to form hydrogels (ca. 1 cm in thickness) with a range of mechanical properties and pH responsiveness, highlighting the potential of the system in materials science.
Investigating Cu(0)‐Mediated Polymerizations: New Kinetic Insights Based on a Comparison of Kinetic Modeling with Experimental Data
Publisher: Wiley
Date: 03-09-2012
Single-Chain Nanoparticles as Catalytic Nanoreactors
Publisher: American Chemical Society (ACS)
Date: 09-04-2018
DOI: 10.1021/JACS.8B02135
Abstract: The need for efficient, tailor-made catalysts has inspired chemists to fuse the design principles of natural enzymes with synthetic macromolecular architectures. A highly interesting pathway mimics a metallo-enzyme's tertiary structure via the target placement of metal-ions in a tailor-made polymeric framework, resulting in catalytically active single-chain nanoparticles. Initial studies reveal unusual and promising effects, regarding both new catalyst characteristics and a high impact on product formation. These multifunctional nanoreactors, constructed from simple folded polymer chains, will lead to advanced bioinspired catalytic systems. As found in enzymes, their impact lies specifically within the defined construction of a polymeric pocket around the catalytic active cores for substrate recognition.
Protection‐Group‐Free Synthesis of Sequence‐Defined Macromolecules via Precision λ‐Orthogonal Photochemistry
Publisher: Wiley
Date: 11-04-2019
Abstract: An advanced light-induced avenue to monodisperse sequence-defined linear macromolecules via a unique photochemical protocol is presented that does not require any protection-group chemistry. Starting from a symmetrical core unit, precision macromolecules with molecular weights up to 6257.10 g mol
Pyrene‐Tagged Chloro Oximes as Ambient‐Light‐Accelerated Ligation Agents
Publisher: Wiley
Date: 10-12-2018
From the Editor's Desk – Polymer Chemistry 2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7PY90196H
Abstract: Editor-in-Chief Christopher Barner-Kowollik introduces the first 2018 issue of Polymer Chemistry .
Bottom‐Up Fabrication of Nanopatterned Polymers on DNA Origami by In Situ Atom‐Transfer Radical Polymerization
Publisher: Wiley
Date: 05-04-2016
Abstract: Bottom-up strategies to fabricate patterned polymers at the nanoscale represent an emerging field in the development of advanced nanodevices, such as biosensors, nanofluidics, and nanophotonics. DNA origami techniques provide access to distinct architectures of various sizes and shapes and present manifold opportunities for functionalization at the nanoscale with the highest precision. Herein, we conduct in situ atom-transfer radical polymerization (ATRP) on DNA origami, yielding differently nanopatterned polymers of various heights. After cross-linking, the grafted polymeric nanostructures can even stably exist in solution without the DNA origami template. This straightforward approach allows for the fabrication of patterned polymers with low nanometer resolution, which provides access to unique DNA-based functional hybrid materials.
Cover Feature: Combining Photodeprotection and Ligation into a Dual‐Color Gated Reaction System (Chem. Eur. J. 71/2020)
Publisher: Wiley
Date: 19-10-2020
Characterization of Oligo(vinyl phosphonate)s by High-Resolution Electrospray Ionization Mass Spectrometry: Implications for the Mechanism of Polymerization
Publisher: American Chemical Society (ACS)
Date: 09-02-2008
DOI: 10.1021/MA702225K
Living star polymer formation: Detailed assessment of poly(acrylate) radical reaction pathways via ESI-MS
Publisher: American Chemical Society (ACS)
Date: 11-04-2008
DOI: 10.1021/MA702552G
Fast and Simple Preparation of Patterned Surfaces with Hydrophilic Polymer Brushes by Micromolding in Capillaries
Publisher: American Chemical Society (ACS)
Date: 08-12-2015
DOI: 10.1021/ACS.LANGMUIR.5B03924
Abstract: Micropatterns of hydrophilic polymer brushes were prepared by micromolding in capillaries (MIMIC). The polymers are covalently bound to the surfaces by a rapid hetero Diels-Alder reaction, constituting the first ex le of polymers grafted to surfaces in a defined pattern by MIMIC. The polymers [poly(acrylic acid), poly(hydroxyethyl acrylate), and poly(tetraethylene glycol acrylate) ranging in molecular weight from 1500 to 6000 g mol(-1)] were prepared with narrow dispersities via the reversible addition-fragmentation chain transfer (RAFT) process using a highly electron deficient RAFT agent that can react with surface-anchored dienes such as cyclopentadiene. We demonstrate that the anchoring method is facile to perform and highly suitable for preparing patterned surfaces that are passivated against biological impact in well-defined areas.
Polymer Science in Undergraduate Chemical Engineering and Industrial Chemistry Curricula: A Modular Approach
Publisher: American Chemical Society (ACS)
Date: 10-2006
DOI: 10.1021/ED083P1521
Contemporary catalyst-free photochemistry in synthetic macromolecular science
Publisher: Elsevier BV
Date: 2020
Polymer on Top: Current Limits and Future Perspectives of Quantitatively Evaluating Surface Grafting
Publisher: Wiley
Date: 07-03-2018
Abstract: Well-defined polymer strands covalently tethered onto solid substrates determine the properties of the resulting functional interface. Herein, the current approaches to determine quantitative grafting densities are assessed. Based on a brief introduction into the key theories describing polymer brush regimes, a user's guide is provided to estimating maximum chain coverage and-importantly-examine the most frequently employed approaches for determining grafting densities, i.e., dry thickness measurements, gravimetric assessment, and swelling experiments. An estimation of the reliability of these determination methods is provided via carefully evaluating their assumptions and assessing the stability of the underpinning equations. A practical access guide for comparatively and quantitatively evaluating the reliability of a given approach is thus provided, enabling the field to critically judge experimentally determined grafting densities and to avoid the reporting of grafting densities that fall outside the physically realistic parameter space. The assessment is concluded with a perspective on the development of advanced approaches for determination of grafting density, in particular, on single-chain methodologies.
Light-induced modification of silver nanoparticles with functional polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC00960F
Abstract: Light coating: Ag–polymer core–shell nanoparticles were prepared using photoenol-based light-induced ligation.
Chain-Length-Dependent Photolysis of
Publisher: American Chemical Society (ACS)
Date: 25-03-2021
DOI: 10.1021/ACSMACROLETT.1C00057
Abstract: Herein, we demonstrate that the photochemical cleavage of linear polymers containing a midchain photocleavable moiety strongly depends on the chain length. Based on an
Exploring the Photochemical Reactivity of Multifunctional Photocaged Dienes in Continuous Flow
Publisher: Wiley
Date: 14-08-2019
A new approach for modular polymer–polymer conjugations via Heck coupling
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2SC20402A
Ambient Temperature Synthesis of a Versatile Macromolecular Building Block: Cyclopentadienyl-Capped Polymers
Publisher: American Chemical Society (ACS)
Date: 08-12-2010
DOI: 10.1021/MA902464A
Cobalt(II)-mediated catalytic chain transfer polymerization of styrene: Estimating individual rate coefficients via kinetic modeling
Publisher: American Chemical Society (ACS)
Date: 28-01-2003
DOI: 10.1021/MA021152C
Diels-Alder reactions as an efficient route to high purity cyclic polymers
Publisher: Wiley
Date: 17-03-2011
Abstract: A simple and efficient route for the synthesis of cyclic polymer systems is presented. Linear furan protected α ‐maleimide‐ ω ‐cyclopentadienyl functionalized precursors (poly(methyl methacrylate) and poly( tert ‐butyl acrylate)) were synthesized via atom transfer radical polymerization (ATRP) and subsequent substitution of the bromine end‐group with cyclopentadiene. Upon heating at high dilution, deprotection of the dieneophile occurs followed by an intramolecular Diels–Alder reaction yielding a high purity cyclic product. magnified image
Mapping Poly(butyl acrylate) Product Distributions by Mass Spectrometry in a Wide Temperature Range: Suppression of Midchain Radical Side Reactions
Publisher: American Chemical Society (ACS)
Date: 09-11-2007
DOI: 10.1021/MA071471+
Using Kinetics and Thermodynamics in the Controlled Synthesis of Low Molecular Weight Polymers in Free-Radical Polymerization
Publisher: Wiley
Date: 04-2001
DOI: 10.1002/1521-3919(20010401)10:4<255::AID-MATS255>3.0.CO;2-V
N. Charton, A. Feldermann, A. Theis, M. H. Stenzel, T. P. Davis, C. Barner‐Kowollik, Initiator efficiency of 2,2′‐azobis(isobutyronitrile) in bulk dodecyl acrylate free‐radical polymerizations over
Publisher: Wiley
Date: 24-09-2004
DOI: 10.1002/POLA.20518
Visible Light-Enabled Switching of Soft Material Properties Based on Thioindigo Photoswitches
Publisher: Research Square Platform LLC
Date: 19-08-2023
DOI: 10.21203/RS.3.RS-3220772/V1
Abstract: Thioindigos are visible light responsive photoswitches with excellent spatial control over the conformational change between their trans- and cis- isomers. However, they possess extremely limited solubility in all conventional organic solvents and polymers, hindering their application in soft matter materials. Herein, we introduce a strategy for the covalent insertion of thioindigo units into polymer main chains, enabling thioindigos to function within crosslinked polymeric hydrogels. We overcome their solubility issues by developing a thioindigo bismethacrylate linker able to undergo radical initiated thiol-ene reaction for step-growth polymerization, generating indigo-containing polymers. The optimal wavelength for the reversible trans- / cis- isomerisation of thioindigo was elucidated by constructing a detailed photochemical action plot of their switching efficiencies at a wide range of monochromatic wavelengths. Critically, indigo-containing polymers display significant photoswitching of the materials’ optical and physical properties in organic solvents and water. Furthermore, the photoswitching of thioindigo within crosslinked structures enables visible light induced modulation of the hydrogel stiffness. Both the thioindigo-containing hydrogels and photoswitching processes are non-toxic to cells, thus offering opportunities for new and advanced applications in soft matter materials and biology-related research.
Macromolecules made to order
Publisher: Springer Science and Business Media LLC
Date: 21-11-2013
DOI: 10.1038/NCHEM.1806
Abstract: Mastering how to completely control the exact monomer sequence of synthetic polymers is the ultimate key for establishing true biomimetic macromolecular chemistry. A versatile one-pot approach for the synthesis of well-defined multiblock copolymers with short block lengths offers another approach on the road towards this lofty goal
Harnessing entropy to direct the bonding/debonding of polymer systems based on reversible chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SC50642H
Stability of Diels–Alder photoadducts in macromolecules
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY00748A
Abstract: The study investigates the thermal stability of ligation points resulting from photochemically induced Diels–Alder reactions within soft matter materials on the molecular level.
Degradable fluorescent single-chain nanoparticles based on metathesis polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6CC08554G
Abstract: We introduce the facile synthesis of fluorescent single-chain nanoparticles (SCNPs) based on chain-shattering acyclic diene metathesis (ADMET) polymers featuring self-immolative azobenzene motifs.
Copolymers of 2-hydroxyethylacrylate and 2-methoxyethyl acrylate by nitroxide mediated polymerization: kinetics, SEC-ESI-MS analysis and thermoresponsive properties
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00344E
Reducing the Degree of Branching in Polyacrylates via Midchain Radical Patching: A Quantitative Melt-State NMR Study
Publisher: American Chemical Society (ACS)
Date: 11-06-2010
DOI: 10.1021/MA100991C
Laser printed microelectronics
Publisher: Springer Science and Business Media LLC
Date: 27-02-2023
DOI: 10.1038/S41467-023-36722-7
Abstract: Printed organic and inorganic electronics continue to be of large interest for sensors, bioelectronics, and security applications. Many printing techniques have been investigated, albeit often with typical minimum feature sizes in the tens of micrometer range and requiring post-processing procedures at elevated temperatures to enhance the performance of functional materials. Herein, we introduce laser printing with three different inks, for the semiconductor ZnO and the metals Pt and Ag, as a facile process for fabricating printed functional electronic devices with minimum feature sizes below 1 µm. The ZnO printing is based on laser-induced hydrothermal synthesis. Importantly, no sintering of any sort needs to be performed after laser printing for any of the three materials. To demonstrate the versatility of our approach, we show functional diodes, memristors, and a physically unclonable function based on a 6 × 6 memristor crossbar architecture. In addition, we realize functional transistors by combining laser printing and inkjet printing.
Postpolymerization Modification of Hydroxyl-Functionalized Polymers with Isocyanates
Publisher: American Chemical Society (ACS)
Date: 26-05-2011
DOI: 10.1021/MA2008018
Entropy‐Driven Selectivity for Chain Scission: Where Macromolecules Cleave
Publisher: Wiley
Date: 10-12-2015
Abstract: We show that, all other conditions being equal, bond cleavage in the middle of molecules is entropically much more favored than bond cleavage at the end. Multiple experimental and theoretical approaches have been used to study the selectivity for bond cleavage or dissociation in the middle versus the end of both covalent and supramolecular adducts and the extensive implications for other fields of chemistry including, e.g., chain transfer, polymer degradation, and control agent addition are discussed. The observed effects, which are a consequence of the underlying entropic factors, were predicted on the basis of simple theoretical models and demonstrated via high-temperature (HT) NMR spectroscopy of self-assembled supramolecular diblock systems as well as temperature-dependent size-exclusion chromatography (TD SEC) of covalently bonded Diels-Alder step-growth polymers.
Quantitative LC−MS of Polymers: Determining Accurate Molecular Weight Distributions by Combined Size Exclusion Chromatography and Electrospray Mass Spectrometry with Maximum Entropy Data Processing
Publisher: American Chemical Society (ACS)
Date: 09-08-2008
DOI: 10.1021/AC800591J
Abstract: We report on the successful application of size exclusion chromatography (SEC) combined with electrospray ionization mass spectrometry (ESI-MS) and refractive index (RI) detection for the determination of accurate molecular weight distributions of synthetic polymers, corrected for chromatographic band broadening. The presented method makes use of the ability of ESI-MS to accurately depict the peak profiles and retention volumes of in idual oligomers eluting from the SEC column, whereas quantitative information on the absolute concentration of oligomers is obtained from the RI-detector only. A sophisticated computational algorithm based on the maximum entropy principle is used to process the data gained by both detectors, yielding an accurate molecular weight distribution, corrected for chromatographic band broadening. Poly(methyl methacrylate) standards with molecular weights up to 10 kDa serve as model compounds. Molecular weight distributions (MWDs) obtained by the maximum entropy procedure are compared to MWDs, which were calculated by a conventional calibration of the SEC-retention time axis with peak retention data obtained from the mass spectrometer. Comparison showed that for the employed chromatographic system, distributions below 7 kDa were only weakly influenced by chromatographic band broadening. However, the maximum entropy algorithm could successfully correct the MWD of a 10 kDa standard for band broadening effects. Molecular weight averages were between 5 and 14% lower than the manufacturer stated data obtained by classical means of calibration. The presented method demonstrates a consistent approach for analyzing data obtained by coupling mass spectrometric detectors and concentration sensitive detectors to polymer liquid chromatography.
Synthesis of Various Glycopolymer Architectures via RAFT Polymerization: From Block Copolymers to Stars
Publisher: American Chemical Society (ACS)
Date: 13-12-2005
DOI: 10.1021/BM0506086
Abstract: Well-defined linear poly(acryloyl glucosamine) (PAGA) exhibiting molar masses ranging from 3 to 120 K and low polydispersities have been prepared via reversible addition-fragmentation chain transfer polymerization (RAFT) in aqueous solution without recourse to protecting group chemistry. The livingness of the process was further demonstrated by successfully chain-extending one of these polymers with N-isopropylacrylamide affording narrow dispersed thermosensitive diblocks. This strategy of polymerization was finally extended to the preparation of glycopolymer stars from Z designed non-water-soluble trifunctional RAFT agent. After the growth of very short blocks of poly(hydroxyethyl acrylate) ((-)DP(n)(branch) = 10), AGA was polymerized in aqueous solution in a controlled manner affording well-defined 3-arm glycopolymer stars.
The application of ionizing radiation in reversible addition-fragmentation chain transfer (RAFT) polymerization: Renaissance of a key synthetic and kinetic tool
Publisher: Elsevier BV
Date: 10-2007
(Ultra)Fast Catalyst-Free Macromolecular Conjugation in Aqueous Environment at Ambient Temperature
Publisher: American Chemical Society (ACS)
Date: 20-04-2012
DOI: 10.1021/JA301762Y
Abstract: Tailor-made water-soluble macromolecules, including a glycopolymer, obtained by living/controlled RAFT-mediated polymerization are demonstrated to react in water with diene-functionalized poly(ethylene glycol)s without pre- or post-functionalization steps or the need for a catalyst at ambient temperature. As previously observed in organic solvents, hetero-Diels-Alder (HDA) conjugations reached quantitative conversion within minutes when cyclopentadienyl moieties were involved. However, while catalysts and elevated temperatures were previously necessary for open-chain diene conjugation, additive-free HDA cycloadditions occur in water within a few hours at ambient temperature. Experimental evidence for efficient conjugations is provided via unambiguous ESI-MS, UV/vis, NMR, and SEC data.
High resolution mass spectrometric access to nitroxide containing polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY01316G
Abstract: We introduce a mass spectrometric access route to nitroxide containing polymers via high resolution electrospray ionization mass spectrometry (HR ESI MS), a polymer class that is – due to the presence of unpaired spins – highly challenging to analyze via NMR techniques.
A qualitative and quantitative post-mortem analysis: Studying free-radical initiation processes via soft ionization mass spectrometry
Publisher: Wiley
Date: 26-04-2012
DOI: 10.1002/POLA.26076
Abstract: The current article contains a review of the electrospray ionization‐mass spectrometry characterization of polymers prepared via thermal‐ and photoinitiation processes. The used analysis method permits direct access to detailed endgroup information. For a qualitative and quantitative endgroup analysis, sophisticated methods have been developed which provide a detailed image of the incorporation propensity of thermally as well as photolytically generated radicals at the polymer chain termini. Such a post‐mortem analysis of polymeric materials specifically allows for the quantification of the ability of radical fragments to initiate polymerization processes. Herein, the most recent progress in the field of mass spectrometric radical reactivity mapping is outlined and open questions as well as future directions are discussed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
A Priori Prediction of Mass Spectrometric Product Patterns of Photoinitiated Polymerizations
Publisher: American Chemical Society (ACS)
Date: 05-01-2018
DOI: 10.1021/ACSMACROLETT.7B00907
Abstract: We introduce a method for the a priori prediction of mass spectra of complex poly(methyl methacrylate)s initiated by photoinitiators featuring multiple cleavage points. The method is based on permutation mathematics using multinomial coefficients to predict the probability of each poly(methyl methacrylate) species' isotopic pattern contribution to the overall mass spectrum. The method assumes a statistical behavior for the cleavage of the photoinitiator. The excellent agreement of the predicted mass spectrum based on multinomial coefficients with the experimental mass spectrum confirms a multipoint cleavage mechanism of the assessed photoinitiators. We exemplify our method for the prediction of mass spectra of poly(methyl methacrylate)s initiated by four tetraacylgermane derivates and one bisacylgermane, recorded after visible light pulsed-laser polymerization by high resolution Orbitrap electrospray ionization mass spectrometry (ESI-MS). The excellent agreement of our approach with experimental data suggests that a wide array of polymer mass spectra of polymers initiated by initiators capable of multiple cleavage events can be quantitatively predicted.
A Subtractive Photoresist Platform for Micro‐ and Macroscopic 3D Printed Structures
Publisher: Wiley
Date: 22-05-2018
Reversible Addition Fragmentation Chain Transfer (RAFT) Polymerization in Undergraduate Polymer Science Lab
Publisher: American Chemical Society (ACS)
Date: 2008
DOI: 10.1021/ED085P97
A Novel One-Pot Procedure for the Fast and Efficient Conversion of RAFT Polymers into Hydroxy-Functional Polymers
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CH09080
Abstract: We report on the successful quantitative transformation of methacrylate and acrylate-type polymers prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization carrying a dithioester-end-group into hydroxy-functional polymers. The simple reaction procedure involves stirring a solution of the dithioester-capped polymer and an azo-initiator in tetrahydrofuran at elevated temperatures (T = 60°C) in the presence of air. This reaction quantitatively yields hydroperoxide functionalities that can be efficiently reduced to hydroxy groups in a one-pot procedure using triphenylphosphine. Size exclusion chromatography–electrospray mass spectrometry was employed to monitor the progress of the reaction. The new backbone-linked hydroxy group provides a versatile anchor for chemical end-group conversions and conjugation reactions with prepared RAFT polymers, which alleviates problems with the rather limited ability of the dithioester-end-group to undergo non-radical transformations.
Access to Intrinsically Glucoside‐Based Microspheres with Boron Affinity
Publisher: Wiley
Date: 27-03-2013
Abstract: Intrinsically glucoside-based microspheres are prepared in olive oil via a water in oil inverse suspension polymerization. The microspheres are characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) microscopy, and X-ray photoelectron spectroscopy (XPS), evidencing the intrinsic glucose character of the spheres. A novel boronic acid fluorescent molecule was subsequently conjugated to the microspheres in an aqueous environment, exhibiting the spatial and uniform distribution of glucoside as well as the affinity of the microspheres to bind with boron, evidenced via fluorescence spectroscopy measurements.
Pushing the limits of single chain compaction analysis by observing specific size reductions via high resolution mass spectrometry
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9PY01910C
Abstract: Herein, we push the limits of single chain nanoparticle analysis to directly observe the specific compaction of defined single chains dependent on the number of compaction steps.
A facile route to segmented copolymers by fusing ambient temperature step-growth and RAFT polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC06347D
Abstract: We introduce the facile synthesis of segmented copolymers via a catalyst-free Diels–Alder (DA) reaction at ambient temperature via step-growth polymerization and subsequent reversible addition fragmentation chain transfer (RAFT) polymerization.
Polyselenoureas via Multicomponent Polymerizations Using Elemental Selenium as Monomer
Publisher: American Chemical Society (ACS)
Date: 11-07-2018
Formation of nanoporous materials via mild retro-Diels-Alder chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0PY00267D
Coding and decoding libraries of sequence-defined functional copolymers synthesized via photoligation
Publisher: Springer Science and Business Media LLC
Date: 30-11-2016
DOI: 10.1038/NCOMMS13672
Abstract: Designing artificial macromolecules with absolute sequence order represents a considerable challenge. Here we report an advanced light-induced avenue to monodisperse sequence-defined functional linear macromolecules up to decamers via a unique photochemical approach. The versatility of the synthetic strategy—combining sequential and modular concepts—enables the synthesis of perfect macromolecules varying in chemical constitution and topology. Specific functions are placed at arbitrary positions along the chain via the successive addition of monomer units and blocks, leading to a library of functional homopolymers, alternating copolymers and block copolymers. The in-depth characterization of each sequence-defined chain confirms the precision nature of the macromolecules. Decoding of the functional information contained in the molecular structure is achieved via tandem mass spectrometry without recourse to their synthetic history, showing that the sequence information can be read. We submit that the presented photochemical strategy is a viable and advanced concept for coding in idual monomer units along a macromolecular chain.
Redox‐Switchable Supramolecular Graft Polymer Formation via Ferrocene–Cyclodextrin Assembly
Publisher: Wiley
Date: 22-04-2014
Abstract: The redox switchable formation of very well-defined supramolecular graft polymers in aqueous solution driven by host-guest interactions between ferrocene (Fc) and cyclodextrin (CD) is presented. The Fc-containing acrylic backbone copolymer (PDMA-stat-Fc) is prepared via reversible addition-fragmentation chain transfer (RAFT) copolymerization of N,N-dimethyl-acrylamide (DMA) and the novel monomer N-(ferrocenoylmethyl)acrylamide (NFMA). Via the RAFT process, copolymers containing variable Fc ratios (5-10 mol%) are prepared, affording polymers of molecular masses of close to 11,000 g mol(-1) and molar mass dispersities (Đ) of 1.2. The β-cyclodextrin (β-CD) containing building block is synthesized via RAFT-polymerization, too, in order to afford a polymer with well-defined molecular mass and low dispersity (Mn = 10 300 g mol(-1) , Đ = 1.1), employing a propargyl-functionalized chain transfer agent for the polymerization of N,N-diethylacrylamide (DEA). The polymerization product is subsequently terminated with β-CD via the regiospecific copper (I)-catalyzed 1,3-cycloaddition (PDEA-βCD). Host-guest interactions between Fc and CD lead to the formation of supramolecular graft-polymers, verified via nuclear Overhauser enhancement spectroscopy (NOESY). Importantly, their redox-responsive character is clearly confirmed via cyclic voltammetry (CV). The self-assembly of the statistical Fc-containing lateral polymer chain in aqueous solution leads to mono- and multi-core micelle-aggregates evidenced via TEM. Only diffused cloud-like, non-spherical nanostructures are observed after addition of PDEA-βCD (TEM).
Heterobimetallic Eu(iii )/Pt(ii ) single-chain nanoparticles: a path to enlighten catalytic reactions
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0SC03579C
Abstract: A bifunctional terpolymer containing two orthogonal ligand moieties was synthesized, giving way to the facile formation of heterometallic Eu( iii )/Pt( ii ) single-chain nanoparticles, which display both catalytic and luminescent properties.
Global Trends for kp? Expanding the Frontier of Ester Side Chain Topography in Acrylates and Methacrylates
Publisher: American Chemical Society (ACS)
Date: 18-12-2012
DOI: 10.1021/MA302319Z
Ubiquitous Nature of Rate Retardation in Reversible Addition–Fragmentation Chain Transfer Polymerization
Publisher: American Chemical Society (ACS)
Date: 18-10-2021
DOI: 10.1021/JACS.1C08654
Abstract: Reversible addition-fragmentation chain transfer (RAFT) polymerization is one of the most powerful reversible deactivation radical polymerization (RDRP) processes. Rate retardation is prevalent in RAFT and occurs when polymerization rates deviate from ideal conventional radical polymerization kinetics. Herein, we explore beyond what was initially thought to be the culprit of rate retardation: dithiobenzoate chain transfer agents (CTA) with more active monomers (MAMs). Remarkably, polymerizations showed that rate retardation occurs in systems encompassing the use of trithiocarbonates and xanthates CTAs with varying monomeric activities. Both the simple slow fragmentation and intermediate radical termination models show that retardation of all these systems can be described by using a single relationship for a variety of monomer reactivity and CTAs, suggesting rate retardation is a universal phenomenon of varying severity, independent of CTA composition and monomeric activity level.
A Combined Photochemical and Multicomponent Reaction Approach to Precision Oligomers
Publisher: Wiley
Date: 05-02-2018
Abstract: We introduce the convergent synthesis of linear monodisperse sequence-defined oligomers through a unique approach, combining the Passerini three-component reaction (P-3CR) and a Diels-Alder (DA) reaction based on photocaged dienes. A set of oligomers is prepared resting on a Passerini linker unit carrying an isocyano group for chain extension by P-3CR and a maleimide moiety for photoenol conjugation enabling a modular approach for chain growth. Monodisperse oligomers are accessible in a stepwise fashion by switching between both reaction types. Employing sebacic acid as a core unit allows the synthesis of a library of symmetric sequence-defined oligomers. The oligomers consist of alternating P-3CR and photoblocks with molecular weights up to 3532.16 g mol
Miktoarm star polymers via cyclodextrin-driven supramolecular self-assembly
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2PY20214J
Verification of controlled grafting of styrene from cellulose via radiation-induced RAFT polymerization
Publisher: American Chemical Society (ACS)
Date: 08-09-2007
DOI: 10.1021/MA070825U
Two colours of light drive PET–RAFT photoligation
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY01078B
Abstract: By fusing the realms of photopolymerisation and photoligation, our contribution exploits two orthogonal wavelengths of visible light to readily synthesise and functionalise well defined polymers from a unique dual functionality RAFT agent.
Design of Experiment (DoE) as a Tool for the Optimization of Source Conditions in SEC‐ESI‐MS of Functional Synthetic Polymers Synthesized via ATRP
Publisher: Wiley
Date: 09-04-2009
Abstract: Design of experiment (DoE) is applied to establish the optimum ionization conditions for analyzing synthetic polymers via coupled size exclusion chromatography electrospray ionization mass spectrometry (SEC-ESI-MS) yielding maximum ionization efficiency. The ion source conditions were optimized with regard to the ionization efficiency, the amount of fragmentation, as well as the formation of salt adducts. A D-optimal experimental design was employed for this purpose and the recorded data were evaluated by a quadratic response surface model, accounting for possible interactions between the in idual source settings. It was established that the ionization efficiency can be improved by up to one order of magnitude without compromising the softness of the ionization process and that optimal ionization conditions are found at similar source settings regardless of the charge state. The present optimization exercise therefore provides a hands-on guide for the use of experimental design to determine optimum ionization conditions during the SEC-ESI-MS of functional polymers.
Fast and Accurate Determination of Absolute Individual Molecular Weight Distributions from Mixtures of Polymers via Size Exclusion Chromatography−Electrospray Ionization Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 07-08-2009
DOI: 10.1021/MA900755Z
Nitrones in synthetic polymer chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0PY00377H
Abstract: Very recently, the development of enhanced spin capturing polymerization (ESCP) and nitrone-mediated radical coupling (NMRC) reactions—based on nitrone chemistry—has opened up novel synthetic avenues in macromolecular engineering. The synthetic potential of nitrones in polymer chemistry is discussed herein.
Visible‐Light‐Induced Passerini Multicomponent Polymerization
Publisher: Wiley
Date: 19-03-2019
Abstract: Herein, we introduce an additive-free visible-light-induced Passerini multicomponent polymerization (MCP) for the generation of high molar mass chains. In place of classical aldehydes (or ketones), highly reactive, in situ photogenerated thioaldehydes are exploited along with isocyanides and carboxylic acids. Prone to side reactions, the thioaldehyde moieties create a complex reaction environment which can be tamed by optimizing the synthetic conditions utilizing stochastic reaction path analysis, highlighting the potential of semi-batch procedures. Once the complex MCP environment is understood, step-growth polymers can be synthesized under mild reaction conditions which-after a Mumm rearrangement-result in the incorporation of thioester moieties directly into the polymer backbone, leading to soft matter materials that can be degraded by straightforward aminolysis or chain expanded by thiirane insertion.
Dynamic Macromolecular Material Design—The Versatility of Cyclodextrin‐Based Host–Guest Chemistry
Publisher: Wiley
Date: 12-06-2017
Abstract: Dynamic and adaptive materials are powerful constructs in macromolecular and polymer chemistry with a wide array of applications in drug delivery, bioactive systems, and self-healing materials. Very often, dynamic materials are based on carefully tailored cyclodextrin host-guest interactions. The precise incorporation of these host and guest moieties into macromolecular building blocks allows the formation of complex macromolecular structures with predefined functions. Thus, dynamic materials with extraordinary adaptive property profiles-responsive to thermal, chemical, and photonic fields-become accessible. This Review explores the hierarchical formation of dynamic materials and complex macromolecular structures from the molecular via the macromolecular to the colloidal and macroscopic level, with a specific emphasis on the functionality and responsiveness of the assemblies, specifically in biological contexts.
Two in One: Light as a Tool for 3D Printing and Erasing at the Microscale
Publisher: Wiley
Date: 16-08-2019
Abstract: The ability to selectively remove sections from 3D-printed structures with high resolution remains a current challenge in 3D laser lithography. A novel photoresist is introduced to enable the additive fabrication of 3D microstructures at one wavelength and subsequent spatially controlled cleavage of the printed resist at another wavelength. The photoresist is composed of a difunctional acrylate cross-linker containing a photolabile o-nitrobenzyl ether moiety. 3D microstructures are written by photoinduced radical polymerization of acrylates using Ivocerin as photoinitiator upon exposure to 900 nm laser light. Subsequent scanning using a laser at 700 nm wavelength allows for the selective removal of the resist by photocleaving the o-nitrobenzyl group. Both steps rely on two-photon absorption. The fabricated and erased features are imaged using scanning electron microscopy (SEM) and laser scanning microscopy (LSM). In addition, a single wire bond is successfully eliminated from an array, proving the possibility of complete or partial removal of structures on demand.
Adding chemically selective subtraction to multi-material 3D additive manufacturing
Publisher: Springer Science and Business Media LLC
Date: 17-07-2018
DOI: 10.1038/S41467-018-05234-0
Abstract: Existing photoresists for 3D laser lithography that can be removed after development in a subtractive manner typically suffer from harsh cleavage conditions. Here, we report chemoselectively cleavable photoresists for 3D laser lithography based on silane crosslinkers, allowing the targeted degradation of 3D printed microstructures under mild conditions. Three bifunctional silane crosslinkers carrying various substitutions on the silicon atom are synthesized. The photoresists are prepared by mixing these silane crosslinkers with pentaerythritol triacrylate and a two-photon photoinitiator. The presence of pentaerythritol triacrylate significantly enhances the direct laser written structures with regard to resolution, while the microstructures remain cleavable. For the targeted cleavage of the fabricated 3D microstructures, simply a methanol solution including inorganic salts is required, highlighting the mild cleavage conditions. Critically, the photoresists can be cleaved selectively, which enables the sequential degradation of direct laser written structures and allows for subtractive manufacturing at the micro- and nanoscale.
Deconstructing 3D Structured Materials by Modern Ultramicrotomy for Multimodal Imaging and Volume Analysis across Length Scales
Publisher: Wiley
Date: 08-07-2023
Abstract: Based on the rapid advances in additive manufacturing, micro‐patterned heterostructures of soft materials have become available that need to be characterized down to the nanoscale. Advanced function‐structure relationships are designed by direct 3D structuring of the object and – in the future – fine control over material functionality in 3D will produce complex functional objects. To control their design, fabrication and final structure, morphological and spectroscopical imaging in 3D at nanometer resolution are critically required. With ex les of carbon‐based objects, it is demonstrated how serial ultramicrotomy, that is, cutting a large number of successive ultrathin sections, can be utilized to gain access to the interior of 3D objects. Array tomography, hierarchical imaging and correlative light and electron microscopy can bridge length scales over several orders of magnitude and provide multimodal information of the s le's inner structure. Morphology data derived from scanning electron microscopy are correlated with spectroscopy in analytical transmission electron microscopy and probe microscopy at nanometer resolution, using TEM‐electron energy loss spectroscopy and infrared‐scanning‐near‐field microscopy. The correlation of different imaging modalities and spectroscopy of carbon‐based materials in 3D provides a powerful toolbox of complementary techniques for understanding emerging functions from nanoscopic structuring.
The interplay of different relaxation channels in the excited state dynamics of photoinitiators
Publisher: EDP Sciences
Date: 2013
Ferrocene-driven single-chain polymer compaction
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3CC00736G
Abstract: We introduce single-chain nanoparticles (SCNPs) whose folding is driven by ferrocene units while concomitantly carrying catalytically active species, establishing a bimetallic SCNP system that pushes the contemporary limits of SCNP design.
Living free radical polymerization (RAFT) of dodecyl acrylate: Chain length dependent termination, mid-chain radicals and monomer reaction order
Publisher: Elsevier BV
Date: 08-2005
Mass Spectrometry in Polymer Chemistry
Publisher: Wiley
Date: 07-12-2011
Photo-induced surface encoding of gold nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CC08880H
Abstract: Writing with gold: a photolithographic approach for the spatially resolved surface encoding of photoreactive gold nanoparticles is shown to enable the generation of highly defined gold surface patterns.
On the Schwarzschild Effect in 3D Two‐Photon Laser Lithography
Publisher: Wiley
Date: 27-08-2019
Propagation Rate Coefficients of Acrylate−Methacrylate Free-Radical Bulk Copolymerizations
Publisher: American Chemical Society (ACS)
Date: 26-06-2001
DOI: 10.1021/MA002231W
Grafting of n-butyl acrylate and N,N '-dimethyl acrylamide from poly(divinylbenzene) microspheres by RAFT polymerization
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/CH05057
Abstract: N,N´-Dimethyl acrylamide and n-butyl acrylate have been grafted from crosslinked poly( inylbenzene) core microspheres by both reversible addition–fragmentation chain transfer (RAFT) polymerization and conventional free radical polymerization. The microspheres were prepared by precipitation polymerization utilizing 55 and 80 wt. % inylbenzene (DVB), respectively. The RAFT agent cumyl dithiobenzoate (CDB) was utilized and grafting was performed in toluene at 80°C with 2,2´-azoisobutyronitrile (AIBN) as thermal initiator. Particle weights increased up to 6% for poly(n-butyl acrylate) and up to 15% for poly(N,N´-dimethyl acrylamide). Grafting from poly(DVB-55) microspheres results in a higher particle weight increase than grafting from poly(DVB-80) microspheres while using the same RAFT agent concentrations. The particle weight increase is approximately higher by a factor of two. The grafted microspheres were characterized by attenuated total reflection (ATR) IR spectroscopy and scanning electron microscopy.
Microspheres from light—a sustainable materials platform
Publisher: Springer Science and Business Media LLC
Date: 09-2022
DOI: 10.1038/S41467-022-32429-3
Abstract: Driven by the demand for highly specialized polymeric materials via milder, safer, and sustainable processes, we herein introduce a powerful, purely light driven platform for microsphere synthesis – including facile synthesis by sunlight. Our light-induced step-growth precipitation polymerization produces monodisperse particles (0.4–2.4 μm) at ambient temperature without any initiator, surfactant, additive or heating, constituting an unconventional approach compared to the classically thermally driven synthesis of particles. The microspheres are formed via the Diels-Alder cycloaddition of a photoactive monomer (2-methylisophthaldialdehyde, MIA) and a suitable electron deficient dienophile (bismaleimide). The particles are stable in the dry state as well as in solution and their surface can be further functionalized to produce fluorescent particles or alter their hydrophilicity. The simplicity and versatility of our approach introduces a fresh opportunity for particle synthesis, opening access to a yet unknown material class.
Automated Data Processing and Quantification in Polymer Mass Spectrometry
Publisher: Wiley
Date: 07-12-2011
Xanthate Mediated Living Polymerization of Vinyl Acetate: A Systematic Variation in MADIX/RAFT Agent Structure
Publisher: Wiley
Date: 06-2003
Wavelength‐Selective Softening of Hydrogel Networks
Publisher: Wiley
Date: 08-08-2021
Abstract: Photoresponsive hydrogels hold key potential in advanced biomedical applications including tissue engineering, regenerative medicine, and drug delivery, as well as intricately engineered functions such as biosensing, soft robotics, and bioelectronics. Herein, the wavelength‐dependent degradation of bio‐orthogonal poly(ethylene glycol) hydrogels is reported, using three selective activation levels. Specifically, three chromophores are exploited, that is, ortho ‐nitrobenzene, dimethyl aminobenzene, and bimane, each absorbing light at different wavelengths. By examining their photochemical action plots, the wavelength‐dependent reactivity of the photocleavable moieties is determined. The wavelength‐selective addressability of in idual photoreactive units is subsequently translated into hydrogel design, enabling wavelength‐dependent cleavage of the hydrogel networks on‐demand. Critically, this platform technology allows for the fabrication of various hydrogels, whose mechanical properties can be fine‐tuned using different colors of light to reach a predefined value, according to the chromophore ratios used. The softening is shown to influence the spreading of pre‐osteoblastic cells adhering to the gels as a demonstration of their potential utility. Furthermore, the materials and photodegradation processes are non‐toxic to cells, making this platform attractive for biomaterials engineering.
Green light LED activated ligation of a scalable, versatile chalcone chromophore
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1PY00533B
Abstract: Herein we present a photoreactive chalcone moiety that can be synthesized at a scale of several grams with ease, and can efficiently undergo a [2 + 2] photocycloaddition with light close to 500 nm as determined by an action plot.
Toward a Quantitative Description of Radical Photoinitiator Structure–Reactivity Correlations
Publisher: American Chemical Society (ACS)
Date: 13-11-2015
Fluorescent polymers from non-fluorescent photoreactive monomers
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC07792J
Abstract: A facile, fast and ambient-temperature avenue towards highly fluorescent polymers is introduced via polymerizing non-fluorescent photoreactive monomers based on light-induced NITEC chemistry, providing a platform technology for fluorescent polymers. The resulting polypyrazolines were analyzed in depth.
Wavelength-Resolved PhotoATRP
Publisher: American Chemical Society (ACS)
Date: 10-01-2022
DOI: 10.1021/JACS.1C11259
Abstract: The careful mapping of photoinduced reversible-deactivation radical polymerizations (RDRP) is a prerequisite for their applications in soft matter materials design. Here, we probe the wavelength-dependent behavior of photochemically induced atom transfer radical polymerization (ATRP) using nanosecond pulsed-laser polymerization (PLP). The photochemical reactivities at identical photon fluxes of methyl acrylate in terms of conversion, number-average molecular weight, and dispersity of the resulting polymers are mapped against the absorption spectrum of the copper(II) catalyst in the range of 305-550 nm. We observe a red shift of the action spectrum relative to the absorption spectrum of the copper(II) catalyst. Both the number-average molecular weight and the dispersity show a wavelength dependence, while the molecular weight and conversion remain linearly correlated. The reported data allow the judicious selection of optimum wavelengths for photoATRP.
Rapid Assembly of Small Materials Building Blocks (Voxels) into Large Functional 3D Metamaterials
Publisher: Wiley
Date: 22-01-2020
Ugi multicomponent reaction to prepare peptide–peptoid hybrid structures with diverse chemical functionalities
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7PY01953J
Abstract: Sequence defined peptide–peptoid hybrids create new opportunities for self-assembled nano-structures.
Frontispiece: All Eyes on Visible‐Light Peroxyoxalate Chemiluminescence Read‐Out Systems
Publisher: Wiley
Date: 02-01-2020
A Modular Fluorescent Probe for Viscosity and Polarity Sensing in DNA Hybrid Mesostructures
Publisher: Wiley
Date: 23-12-2020
Abstract: There exists a critical need in biomedical molecular imaging and diagnostics for molecular sensors that report on slight changes to their local microenvironment with high spatial fidelity. Herein, a modular fluorescent probe, termed StyPy, is rationally designed which features i) an enormous and tunable Stokes shift based on twisted intramolecular charge transfer (TICT) processes with no overlap, a broad emission in the far‐red/near‐infrared (NIR) region of light and extraordinary quantum yields of fluorescence, ii) a modular applicability via facile para ‐fluoro‐thiol reaction (PFTR), and iii) a polarity‐ and viscosity‐dependent emission. This renders StyPy as a particularly promising molecular sensor. Based on the thorough characterization on the molecular level, StyPy reports on the viscosity change in all‐DNA microspheres and indicates the hydrophilic and hydrophobic compartments of hybrid DNA‐based mesostructures consisting of latex beads embedded in DNA microspheres. Moreover, the enormous Stokes shift of StyPy enables one to detect multiple fluorophores, while using only a single laser line for excitation in DNA protocells. The authors anticipate that the presented results for multiplexing information are of direct importance for advanced imaging in complex soft matter and biological systems.
Self-Reporting Fluorescent Step-Growth RAFT Polymers Based on Nitrile Imine-Mediated Tetrazole-ene Cycloaddition Chemistry
Publisher: American Chemical Society (ACS)
Date: 17-02-2017
A Parallelised High Performance Monte Carlo Simulation Approach for Complex Polymerisation Kinetics
Publisher: Wiley
Date: 21-08-2007
Time‐Dependent Differential and Integral Quantum Yields for Wavelength‐Dependent [4+4] Photocycloadditions
Publisher: Wiley
Date: 12-12-2019
Abstract: The [4+4] photocycloaddition of anthracene is one of most relevant photoreactions and is widely applied in materials science, as it allows to remote-control soft matter material properties by irradiation. However, highly energetic UV irradiation is commonly applied, which limits its application. Herein, the wavelength dependence of the photodimerization of anthracene is assessed for the first time, revealing that the reaction is induced just as effectively with mild visible light (410 nm). To fully establish [4+4] cycloadditions within defined chemical environments, a conceptual framework for the solution kinetics of the photo-dimerization up to long reaction times is established by developing a novel photoreaction rate law that is dependent on in idual rate coefficients of the key reaction steps. These coefficients can be determined based on low conversion photochemical experiments. Both differential and integral quantum yields can subsequently be predicted that are strongly time-dependent, highlighting the need for a detailed reaction pathway analysis. The presented approach simplifies a complex photochemical scenario, making the photochemical anthracene dimerization, or potentially any other photochemical dimerization, amenable to a time-dependent understanding at the elementary reaction level.
A holistic approach for anthracene photochemistry kinetics
Publisher: Elsevier BV
Date: 12-2020
Auto-catalysed crosslinking for next-generation OLED-design
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM33291D
A Synthetic Approach to a Novel Class of Fluorine-Bearing Reversible Addition - Fragmentation Chain Transfer (RAFT) Agents: F-RAFT
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/CH05069
Abstract: A synthetic route is described to a novel class of reversible addition–fragmentation chain transfer (RAFT) agents bearing a fluorine Z-group. Such F-RAFT agents are theoretically predicted to allow living free radical polymerization of various monomers without affecting the rate of polymerization, and should also facilitate the construction of block copolymers from monomers with disparate reactivity. The class of F-RAFT agents is exemplified by the ex le of benzyl fluoro dithioformate (BFDF) in styrene free-radical polymerizations and the process is shown to induce living polymerization.
Sequence-independent activation of photocycloadditions using two colours of light
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1SC06154B
Abstract: We exploit two reactive chromophores to establish sequence-independent photochemical activation without any additives.
Termination Kinetics in Free-Radical Bulk Copolymerization: The Systems Dodecyl Acrylate−Dodecyl Methacrylate and Dodecyl Acrylate−Methyl Acrylate
Publisher: American Chemical Society (ACS)
Date: 19-02-1999
DOI: 10.1021/MA9814806
Advanced Strategies for Spatially Resolved Surface Design via Photochemical Methods
Publisher: Wiley
Date: 08-05-2015
Photodynamic covalent bonds regulated by visible light for soft matter materials
Publisher: Elsevier BV
Date: 04-2022
Dual-Gated Microparticles for Switchable Antibody Release
Publisher: American Chemical Society (ACS)
Date: 20-12-2017
Abstract: We pioneer the design of dual-gated microparticles, both responsive to changes in temperature and pH, for stimuli-responsive chromatography targeted at the efficient separation of antibodies. Dual-gated microspheres were synthesized by introducing RAFT-based thiol-terminal block copolymers of poly(N-isopropylacrylamide-b-4-vinylpyridine) (P(NIPAM-b-4VP, 4800 ≤ M
Gold-Loaded Organic/Inorganic Nanocomposite Honeycomb Membranes
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/CH06173
Abstract: RAFT polymerization was used to prepare polystyrene – poly(4-vinyl pyridine) block copolymers, PSn-b-P(4VP)m. Well-defined block copolymers were obtained despite some indications of hydrolysis of the RAFT endgroup during synthesis. The block copolymer PS70-b-P(4VP)55 was self-assembled into micellar structures in dichloromethane, leading to nanoparticles with hydrodynamic diameters of 70 nm. The micelles were loaded with HAuCl4 and, upon reduction, micellar gold-containing nanoparticles with hydrodynamic diameters of 240 nm were obtained. These nanoparticles were employed in the preparation of honeycomb-structured porous films by means of the breath figures technique to yield gold nanocomposites with a hexagonal porous array.
Termination kinetics in free-radical bulk terpolymerization — the systems methyl acrylate - butyl acrylate - dodecyl acrylate and methyl methacrylate - butyl methacrylate - dodecyl methacrylate
Publisher: Wiley
Date: 07-1999
DOI: 10.1002/(SICI)1521-3935(19990701)200:7<1764::AID-MACP1764>3.0.CO;2-F
Graft block copolymers of propargyl methacrylate and vinyl acetate via a combination of RAFT/MADIX and click chemistry: Reaction analysis
Publisher: Wiley
Date: 21-11-2008
DOI: 10.1002/POLA.22367
Wavelength-Dependent Photochemical Stability of Photoinitiator-Derived Macromolecular Chain Termini
Publisher: American Chemical Society (ACS)
Date: 16-08-2017
Enlightening the Mechanism of Copper Mediated PhotoRDRP via High-Resolution Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 22-05-2015
DOI: 10.1021/JACS.5B03048
Abstract: The initiation mechanism of photochemically mediated Cu-based reversible-deactivation radical polymerization (photoRDRP) was investigated using pulsed-laser polymerization (PLP) and high-resolution mass spectrometry. The variation of the catalyst composition and ESI-MS analysis of the resulting products provided information on how initiator, ligand, copper species, and monomer are interacting upon irradiation with UV light. A discussion of the results allows for a new postulation of the mechanism of photoRDRP and-for the first time-the unambiguous identification of the initiating species and their interactions within the reaction mixture. One pathway for radical generation proceeds via UV light-induced C-Br bond scission of the initiator, giving rise to propagating radicals. The generation of copper(I) species from copper(II) can occur via several pathways, including, among others, via reduction by free amine ligand in its excited as well as from its ground state via the irradiation with UV light. The amine ligand serves as a strong reducing agent and is likely the main participant in the generation of copper(I) species.
Kinetic and Mechanistic Similarities between Reversible Addition Fragmentation Chain Transfer Intermediate and Acrylate Midchain Radicals
Publisher: Wiley
Date: 11-01-2011
DOI: 10.1002/POLA.24546
Addition-fragmentation kinetics of fluorodithioformates (F-RAFT) in styrene, vinyl acetate, and ethylene polymerization: An Ab initio investigation
Publisher: American Chemical Society (ACS)
Date: 24-05-2006
DOI: 10.1021/MA060470Z
Degradation of Poly(methyl methacrylate) Model Compounds at Constant Elevated Temperature Studied via High Resolution Electrospray Ionization Mass Spectrometry (ESI‐MS)
Publisher: Wiley
Date: 10-08-2007
Photo‐Induced Functionalization of Spherical and Planar Surfaces via Caged Thioaldehyde End‐Functional Polymers
Publisher: Wiley
Date: 14-07-2014
Spatially resolved coding of λ-orthogonal hydrogels by laser lithography
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CC09619D
Abstract: A λ-orthogonal reaction system is introduced, where visible light induced radical thiol–ene and UV light induced NITEC (Nitrile-Imine mediated Tetrazole–Ene Conjugation) ligations are consecutively employed to fabricate and functionalize PEG-based hydrogels.
Transfer Reactions in Phenyl Carbamate Ethyl Acrylate Polymerizations
Publisher: Wiley
Date: 29-10-2012
Three‐Dimensional Microscaffolds Exhibiting Spatially Resolved Surface Chemistry
Publisher: Wiley
Date: 04-09-2013
Abstract: Spatial control over the surface chemistry of 3D organic-inorganic hybrid microscaffolds is achieved by a two-photon-triggered cycloaddition. Following a coating step with photoactivatable dienes via silanization, surface irradiation with a femtosecond-pulsed laser in the presence of functional dienophiles enables a site-selective alteration of the surface chemistry. Bioconjugation with fluorescent protein tags is employed to reveal the 3D molecular patterns.
Radical-Induced Single-Chain Collapse of Passerini Sequence-Regulated Polymers Assessed by High-Resolution Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 15-05-2018
α,ω-Reactive Building Blocks Based on a Dual Functional RAFT Agent for Thermal and Light-Induced Ligation
Publisher: American Chemical Society (ACS)
Date: 27-04-2016
Mapping Photochemical Reactivity Profiles on Surfaces
Publisher: American Chemical Society (ACS)
Date: 18-12-2020
DOI: 10.1021/JACS.0C11485
Tunable Blocking Agents for Temperature-Controlled Triazolinedione-Based Cross-Linking Reactions
Publisher: American Chemical Society (ACS)
Date: 11-04-2018
Easy Access to Chain-Length-Dependent Termination Rate Coefficients Using RAFT Polymerization
Publisher: Wiley
Date: 11-2002
DOI: 10.1002/1521-3927(200211)23:16<952::AID-MARC952>3.0.CO;2-F
The Kinetics of enhanced spin capturing polymerization: Influence of the nitrone structure
Publisher: Wiley
Date: 08-01-2009
DOI: 10.1002/POLA.23221
Abstract: Several nitrones and one nitroso compound have been evaluated for their ability to control the molecular weight of polystyrene via the recently introduced radical polymerization method of enhanced spin capturing polymerization (ESCP). In this technique, molecular weight control is achieved (at ambient or slightly elevated temperatures) via the reaction of a growing radical chain with a nitrone forming a macronitroxide. These nitroxides subsequently react rapidly and irreversibly with propagating macroradicals forming polymer of a certain chain length, which depends on the nitrone concentration in the system. Via evaluation of the resulting number‐average molecular weight, M n , at low conversions, the addition rate coefficient of the growing radicals onto the different nitrones is determined and activation energies are obtained. For the nitrones N ‐ tert ‐butyl‐α‐phenylnitrone (PBN), N ‐methyl‐α‐phenylnitrone (PMN), and N ‐methyl‐α‐(4‐bromo‐phenyl) nitrone ( p B‐PMN), addition rate coefficients, k ad,macro , in a similar magnitude to the styrene propagation rate coefficient, k p , are found with spin capturing constants C SC (with C SC = k ad,macro / k p ) ranging from 1 to 13 depending on the nitrone and on temperature. Activation energies between 23.6 and 27.7 kJ mol −1 were deduced for k ad,macro , congruent with a decreasing C SC with increasing temperature. Almost constant M n over up to high monomer to polymer conversions is found when C SC is close to unity, while increasing molecular weights can be observed when the C SC is large. From temperatures of 100 °C onward, reversible cleavage of the alkoxyamine group can occur, superimposing a reversible activation/deactivation mechanism onto the ESCP system. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1098–1107, 2009
Ambient temperature synthesis of well-defined microspheres via precipitation polymerization initiated by UV-irradiation
Publisher: Wiley
Date: 19-06-2007
DOI: 10.1002/POLA.22132
Systematic Assessment of the Photochemical Stability of Photoinitiator-Derived Macromolecular Chain Termini
Publisher: American Chemical Society (ACS)
Date: 20-11-2015
DNA–Polymer Nanostructures by RAFT Polymerization and Polymerization‐Induced Self‐Assembly
Publisher: Wiley
Date: 17-06-2020
Emissive semi-interpenetrating polymer networks for ink-jet printed multilayer OLEDs
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1PY00794G
Abstract: Solution-processing of multi-layered Organic Light Emitting Diodes (OLEDs) remains challenging. Herein, we introduce a facile blending process of emitting polymers with photoreactive polymer strands, allowing for the generation of solvent resistant emissive layers.
Laser‐induced decomposition of 2,2‐dimethoxy‐2‐phenylacetophenone and benzoin in methyl methacrylate homopolymerization studied via matrix‐assisted laser desorption/ionization time‐of‐flight mass spec
Publisher: Wiley
Date: 15-01-2002
DOI: 10.1002/POLA.10150
Ab Initio Kinetic Modelling in Radical Polymerization: A Paradigm Shift in Reaction Kinetic Analysis
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/CH06194
Abstract: We describe a new rationale to kinetic modelling in which adjustable parameters are avoided through the use of quantum chemistry. This new approach reverses the standard modelling approach in which, having first assumed a kinetic model, it is then fitted to the experimentally determined values of the macroscopic properties (rates, compositions, molecular weight distributions, and so forth) so as to estimate the rate coefficients of the in idual reactions. Instead, one still assumes a reaction scheme, but then calculates the rates of the in idual reactions using high-level ab initio calculations, and in this way a kinetic model is built that can be used to predict the macroscopic properties of the process from first principles. These can then be compared directly with experiment (for benchmarking purposes) and subsequently be employed to predict the outcome of new chemical processes. In here we illustrate the ab initio modelling technique, using a recent study of initialization in RAFT polymerization as a case study. We also discuss its advantages and possible problems, and highlight some of its potential applications in the radical polymer field.
Photo-induced ring-closure: Via a looped flow reactor
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7RE00124J
Abstract: Looped flow processes are an efficient and versatile tool to synthesize cyclic macromolecular materials.
It's in the Fine Print: Erasable Three‐Dimensional Laser‐Printed Micro‐ and Nanostructures
Publisher: Wiley
Date: 23-01-2020
Synthesis, multilayer film assembly, and capsule formation of macromolecularly engineered acrylic acid and styrene sulfonate block copolymers
Publisher: American Chemical Society (ACS)
Date: 19-07-2008
DOI: 10.1021/LA8011074
Abstract: We report the use of copolymers synthesized with specific block ratios of weakly and strongly charged groups for the preparation of stable, pH-responsive multilayers. In this study, we utilized reversible addition-fragmentation chain transfer (RAFT) polymerization in the synthesis of novel pH-sensitive copolymers comprising block domains of acrylic acid (AA) and styrene sulfonate (SS) groups. The PAA x- b-SS y copolymers, containing 37%, 55%, and 73% of AA groups by mass (denoted as PAA 37- b-SS 63, PAA 55- b-SS 45, and PAA 73- b-SS 27, respectively), were utilized to perform stepwise multilayer assembly in alternation with poly(allylamine hydrochloride), PAH. The ratio of AA to SS groups, and the effect of the pH of both anionic and cationic adsorption solutions, on multilayer properties, were investigated using ellipsometry and atomic force microscopy. The presence of SS moieties in the PAA x- b-SS y copolymers, regardless of the precise composition, lead to films with a relatively consistent thickness. Exposure of these multilayers to acidic conditions postassembly revealed that these multilayers do not exhibit the characteristic large swelling that occurs with PAA/PAH films. The film stability was attributed to the presence of strongly charged SS groups. PAA x- b-SS y/PAH films were also formed on particle substrates under various adsorption conditions. Microelectrophoresis measurements revealed that the surface charge and isoelectric point of these core-shell particles are dependent on assembly pH and the proportion of AA groups in PAA x- b-SS y. These core-shell particles can be used as precursors to hollow capsules that incorporate weak polyelectrolyte functionality. The role of AA groups in determining the growth profile of these capsules was also examined. The multilayer films prepared may find applications in areas where pH-responsive films are required but large film swelling is unfavorable.
Wavelength-gated photoreversible polymerization and topology control
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SC05381F
Abstract: We exploit the wavelength dependence of [2 + 2] photocycloadditions and -reversions of styrylpyrene to exert unprecedented control over the photoreversible polymerization and topology of telechelic building blocks.
(Meth)acrylic monomers with heteroatom-containing ester side chains: a systematic PLP-SEC and polymerization study
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3PY00948C
Cleaning the Click: A Simple Electrochemical Avenue for Copper Removal from Strongly Coordinating Macromolecules
Publisher: American Chemical Society (ACS)
Date: 17-02-2015
Inside Back Cover: Visible‐Light‐Induced Click Chemistry (Angew. Chem. Int. Ed. 35/2015)
Publisher: Wiley
Date: 17-07-2015
Photochemistry in Confined Environments for Single-Chain Nanoparticle Design
Publisher: American Chemical Society (ACS)
Date: 02-07-2018
DOI: 10.1021/JACS.8B04531
Abstract: Emulating nature's protein paradigm, single-chain nanoparticles (SCNP) are an emerging class of nanomaterials. Synthetic access to SCNPs is limited by ultralow concentrations, demanding reaction conditions, and complex isolation procedures after single-chain collapse. Herein, we exploit the visible light photodimerization of styrylpyrene units as chain folding mechanism. Critically, their positioning along the polymer chain creates a confined environment, increasing the photocycloaddition quantum yields dramatically, enabling single-chain folding at unrivaled high concentrations without subsequent purification. Importantly, the enhanced photoreactivity allows for single-chain folding at λ = 445 nm LED-irradiation within minutes as well as via ambient light, enabling an unprecedented folding system. The herein demonstrated enhancement of quantum yields by steric confinement serves as a blueprint for all photochemical ligation systems.
Two Grapes Short of a Fruit Salad: Raspberry-, Strawberry-, and Seedpod-Like Organic Microspheres via Colloidal Nanotemplating
Publisher: American Chemical Society (ACS)
Date: 23-11-2020
Catalyst free visible light induced cycloaddition as an avenue for polymer ligation
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC00942E
Abstract: The current study introduces a tetrazole species able to perform a rapid, visible light induced nitrile imine-mediated tetrazole-ene cycloaddition (NITEC).
Light- and mechanic field controlled dynamic soft matter materials
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2PY00892K
Abstract: A photochemical reaction system that fuses photo- and mechanochemistry into one macromolecular design for light- and mechano-reversible modification of polymer endgroups is introduced.
Complex macromolecular architectures by reversible addition fragmentation chain transfer chemistry: Theory and practice
Publisher: Wiley
Date: 03-2007
Cover Feature: A Photochemical Ligation System Enabling Solid‐Phase Chemiluminescence Read‐Out (Chem. Eur. J. 54/2019)
Publisher: Wiley
Date: 02-08-2019
Mapping Photolysis Product Radical Reactivities via Soft Ionization Mass Spectrometry in Acrylate, Methacrylate, and Itaconate Systems
Publisher: American Chemical Society (ACS)
Date: 16-08-2007
DOI: 10.1021/MA070626A
Well-Defined Glycopolymers from RAFT Polymerization: Poly(methyl 6-O-methacryloyl-α-d -glucoside) and Its Block Copolymer with 2-Hydroxyethyl Methacrylate
Publisher: American Chemical Society (ACS)
Date: 08-09-2004
DOI: 10.1021/MA049129+
Strongly electron deficient sulfonyldithioformate based RAFT agents for hetero Diels‐Alder conjugation: Computational design and experimental evaluation
Publisher: Wiley
Date: 07-10-2009
DOI: 10.1002/POLA.23647
It’s a Trap: Thiol‐Michael Chemistry on a DASA Photoswitch
Publisher: Wiley
Date: 14-01-2019
Abstract: Donor-acceptor Stenhouse adducts (DASA) are popular photoswitches capable of toggling between two isomers depending on the light and temperature of the system. The cyclized polar form is accessed by visible-light irradiation, whereas the linear nonpolar form is recovered in the dark. Upon the formation of the cyclized form, the DASA contains a double bond featuring a β-carbon prone to nucleophilic attack. Here, an isomer selective thiol-Michael reaction between the cyclized DASA and a base-activated thiol is introduced. The thiol-Michael addition was carried out with an alkyl (1-butanethiol) and an aromatic thiol (p-bromothiophenol) as reaction partners, both in the presence of a base. Under optimized conditions, the reaction proceeds preferentially in the presence of light and base. The current study demonstrates that DASAs can be selectively trapped in their cyclized state.
Formation of triblock copolymers via a tandem enhanced spin capturing-nitroxide-mediated polymerization reaction sequence
Publisher: Wiley
Date: 09-09-2011
DOI: 10.1002/POLA.24970
Abstract: The preparation of ABA‐type block copolymers via tandem enhanced spin capturing polymerization (ESCP) and nitroxide‐mediated polymerization (NMP) processes is explored in‐depth. Midchain alkoxyamine functional polystyrenes ( M n = 6200, 12,500 and 19,900 g mol −1 ) were chain extended with styrene as well as tert ‐butyl acrylate at elevated temperature NMP conditions ( T = 110 °C) generating a tandem ESCP‐NMP sequence. Although the chain extensions and thus the block copolymer formation processes function well (yielding in the case of the chain extension with styrene number average molecular weights of up to 20,800 g mol −1 (PDI = 1.22) when the 6200 g mol −1 precursor is used and up to 67,500 g mol −1 (PDI = 1.36) when the 19,900 g mol −1 precursor is used and 21,600 g mol −1 (PDI = 1.17) as well as 37,100 g mol −1 (PDI = 1.21) for the tert ‐butyl acrylate chain extensions for the 6200 and 12,500 g mol −1 precursors, respectively), it is also evident that the efficiency of the block copolymer formation process decreases with an increasing chain length of the ESCP precursor macromolecules (i.e., for the 19,900 g mol −1 ESCP precursor no efficient chain extension with tert ‐butyl acrylate can be observed). For the polystyrene‐ block ‐ tert ‐butyl acrylate‐ block ‐polystyrene polymers, the molecular weights were determined via triple detection SEC using light scattering and small‐angle X‐ray scattering. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Heterobimetallic Au(i )/Y(iii ) single chain nanoparticles as recyclable homogenous catalysts
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1PY00552A
Abstract: Au( i )/Y( iii ) single chain nanoparticles (SCNPs) are potent homogenous, recyclable catalysts for the hydroamination. The SCNPs consist of terpolymer chains with orthogonal ligand units, enabling the selective embedding of different metals.
Access to cyclic polystyrenes via a combination of reversible addition fragmentation chain transfer (RAFT) polymerization and click chemistry
Publisher: Elsevier BV
Date: 04-2008
Functionalization of Fullerenes with Cyclopentadienyl and Anthracenyl Capped Polymeric Building Blocks via Diels–Alder Chemistry
Publisher: Wiley
Date: 13-07-2010
Abstract: Cyclopentadienyl (Cp) capped polymers [polyethylene glycols (PEGs), $\\overline M _{\\rm n}$ = 2 000 g · mol(-1) ], react readily with fullerenes in a 1:1 molar ratio (relative to the amount of fullerenes and Cp-end groups) at ambient temperature within 5 min in the absence of any catalyst in a Diels-Alder (DA) reaction to provide fullerene-PEG hybrids. Similarly, anthracenyl capped PEGs react with fullerenes (in a 1:3 molar ratio) in DA reactions to yield the corresponding hybrids, albeit over a period of 1.5 h at 80 °C and a lesser conversion. The efficiency of the transformation is monitored via electrospray ionization mass spectrometry (ESI-MS), demonstrating that the fullerenes can be transformed into polymer hybrids most efficiently when Cp-functional polymer is used as the diene. In addition, the obtained hybrids were subjected to UV/Vis as well as thermogravimetric analysis further underpinning the formation of mono-substituted C(60) -PEG hybrids [wt.-%(exp) 70 ± 5 (PEG), 30 ± 5 (C(60) ), wt.-%(theo) 68 (PEG), 32 (C(60) )].
Acrylate Free Radical Polymerization: From Mechanism to Polymer Design
Publisher: Wiley
Date: 12-2009
Wavelength-resolved near infra-red light induced free-radical polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3PY01097J
Photo- and Metallo-responsive N-Alkyl α-Bisimines as Orthogonally Addressable Main-Chain Functional Groups in Metathesis Polymers
Publisher: American Chemical Society (ACS)
Date: 05-01-2016
DOI: 10.1021/JACS.5B12198
Abstract: N-alkyl α-bisimines were employed as main-chain functional groups in acyclic diene metathesis (ADMET)-polymers, conferring dual responsiveness for the controlled switching of the polymeric particle shape with light and metal ions. Photochemical Z/E-isomerization leads to a significant and reversible change in hydrodynamic volume, thus introducing simple imines as novel photoswitches for light-responsive materials. Mild imine-directed CH activation by Pd(OAc)2 is demonstrated as a new single-chain nanoparticle (SCNP) folding process, enabling a controlled atom- and step-economic SCNP synthesis. The combination of light- and metallo-responsiveness in the same polymer provides the ability for orthogonal switching, a valuable tool for advanced functional material design.
Wavelength-selective light-matter interactions in polymer science
Publisher: Elsevier BV
Date: 07-2021
Orthogonal ligation to spherical polymeric microparticles: Modular approaches for surface tailoring
Publisher: Elsevier BV
Date: 07-2012
Controlling biofilm formation with nitroxide functional surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9PY00690G
Abstract: Nitroxide functional polymer coatings with inherent antibiofilm activity are introduced as an avenue to combat bacterial biofilm contamination of medical devices.
Photochemical Design of Functional Fluorescent Single-Chain Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 02-06-2014
DOI: 10.1021/MZ500292E
Abstract: We report the facile ambient temperature generation of size tunable and well-defined (pro)fluorescent single-chain nanoparticles (SCNPs) via the photoinduced nitrile imine intramolecular cross-ligation of linear precursor polymers, constituting a platform technology as novel imaging agents. A set of three linear precursor polymers (
Conducting Polymer/SWCNTs Modular Hybrid Materials via Diels–Alder Ligation
Publisher: American Chemical Society (ACS)
Date: 28-03-2013
DOI: 10.1021/MA4004055
Living free‐radical polymerization of sterically hindered monomers: Improving the understanding of 1,1‐disubstituted monomer systems
Publisher: Wiley
Date: 24-04-2006
DOI: 10.1002/POLA.21470
Ultrafast Click Conjugation of Macromolecular Building Blocks at Ambient Temperature
Publisher: Wiley
Date: 10-03-2009
Abstract: Block copolymers in seconds: Catalyst-free, ambient-temperature click conjugation of in idual polymer strands becomes possible using novel ATRP-derived cyclopentadienyl-capped polymers in an extremely rapid hetero-Diels-Alder cycloaddition with macromolecules equipped with electron-deficient dithioester end groups prepared by the RAFT process.
Photochemically Driven Polymeric Network Formation: Synthesis and Applications
Publisher: Wiley
Date: 11-01-2017
Abstract: Polymeric networks have been intensely investigated and a large number of applications have been found in areas ranging from biomedicine to materials science. Network fabrication via light-induced reactions is a particularly powerful tool, since light provides ready access to temporal and spatial control, opening an array of synthetic access routes for structuring the network geometry as well as functionality. Herein, the most recent light-induced modular reactions and their use in the formation of precision polymeric networks are collated. The synthetic strategies including photoinduced thiol-based reactions, Diels-Alder systems, and photogenerated reactive dipoles, as well as photodimerizations, are discussed in detail. Importantly, applications of the fabricated networks via the aforementioned reactions are highlighted with selected ex les. Concomitantly, we provide future directions for the field, emphasizing the most critically required advances.
Mapping Chain Length and Conversion Dependent Termination Rate Coefficients in Methyl Acrylate Free Radical Polymerization
Publisher: American Chemical Society (ACS)
Date: 11-2005
DOI: 10.1021/MA051370G
Living star polymer formation (RAFT) studied via electrospray ionization mass spectrometry
Publisher: Wiley
Date: 25-01-2008
DOI: 10.1002/POLA.22562
Photochemical ligation meets nanocellulose: a versatile platform for self-reporting functional materials
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8MH00241J
Abstract: The fusion of tetrazole/maleimide-based photochemical ligation (self-reporting, selective) with cellulose nanofibrils (good mechanical properties, biocompatible, sustainable) establishes a versatile platform for bio-based advanced materials.
Light-Adaptive Supramolecular Nacre-Mimetic Nanocomposites
Publisher: American Chemical Society (ACS)
Date: 27-07-2016
DOI: 10.1021/ACS.NANOLETT.6B02127
Abstract: Nature provides design paradigms for adaptive, self-healing, and synergistic high-performance structural materials. Nacre's brick-and-mortar architecture is renowned for combining stiffness, toughness, strength, and lightweightness. Although elaborate approaches exist to mimic its static structure and performance, and to incorporate functionalities for the engineering world, there is a profound gap in addressing adaptable mechanical properties, particularly using remote, quick, and spatiotemporal triggers. Here, we demonstrate a generic approach to control the mechanical properties of nacre-inspired nanocomposites by designing a photothermal energy cascade using colloidal graphene as light-harvesting unit and coupling it to molecularly designed, thermoreversible, supramolecular bonds in the nanoconfined soft phase of polymer/nanoclay nacre-mimetics. The light intensity leads to adaptive steady-states balancing energy uptake and dissipation. It programs the mechanical properties and switches the materials from high stiffness/strength to higher toughness within seconds under spatiotemporal control. We envisage possibilities beyond mechanical materials, for ex le, light-controlled (re)shaping or actuation in highly reinforced nanocomposites.
Wavelength‐Selective Folding of Single Polymer Chains with Different Colors of Visible Light
Publisher: Wiley
Date: 10-09-2019
Abstract: Photochemistry allows chemists to exert control over chemical reactions with spatiotemporal precision. Furthermore, light holds the potential to not only gate when and where but also which reaction takes place. Herein, two photocycloaddition reactions-initiated by different colors of visible light-are utilized to control the intramolecular crosslinking of single polymer chains. Irradiation with blue light (λ
Frontispiece: Contemporary Photoligation Chemistry: The Visible Light Challenge
Publisher: Wiley
Date: 12-03-2019
Photoinduced Tetrazole‐Based Functionalization of Off‐Stoichiometric Clickable Microparticles
Publisher: Wiley
Date: 06-01-2017
Nitrone-mediated radical coupling reactions: A new synthetic tool exemplified on dendrimer synthesis
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CC10322A
Abstract: A synthetic strategy employing nitrones as radical spin traps is presented on the ex le of the efficient generation of novel dendrimers via a combination of radical and classical ‘click’ chemistry.
Evolution of molecular weight distributions in the catalytic chain transfer polymerization of methyl methacrylate up to high monomer conversions
Publisher: Wiley
Date: 2000
DOI: 10.1002/1099-0518(20000915)38:18<3303::AID-POLA90>3.0.CO;2-5
Precisely Controlled Microsphere Design via Visible‐Light Cross‐Linking of Functional Prepolymers
Publisher: Wiley
Date: 30-09-2019
Pushing the limit: Pulsed laser polymerization of n-butyl acrylate at 500 Hz
Publisher: American Chemical Society (ACS)
Date: 04-11-2008
DOI: 10.1021/MA8020932
Selective Dispersion of Single-Walled Carbon Nanotubes with Specific Chiral Indices by Poly(N-decyl-2,7-carbazole)
Publisher: American Chemical Society (ACS)
Date: 20-12-2010
DOI: 10.1021/JA105722U
Abstract: Physico-chemical methods to sort single-walled carbon nanotubes (SWNTs) by chiral index are presently lacking but are required for in-depth experimental analysis and also for potential future applications of specific species. Here we report the unexpected selectivity of poly(N-decyl-2,7-carbazole) to almost exclusively disperse semiconducting SWNTs with differences of their chiral indices (n - m) ≥ 2 in toluene. The observed selectivity complements perfectly the dispersing features of the fluorene analogue poly(9,9-dialkyl-2,7-fluorene), which disperses semiconducting SWNTs with (n - m) ≤ 2 in toluene. The dispersed s les are further purified by density gradient centrifugation and analyzed by photoluminescence excitation spectroscopy. All-atom molecular modeling with decamer model compounds of the polymers and (10,2) and (7,6) SWNTs suggests differences in the π-π stacking interaction as origin of the selectivity. We observe energetically favored complexes between the (10,2) SWNT and the carbazole decamer and between the (7,6) SWNT and the fluorene decamer, respectively. These findings demonstrate that subtle structural changes of polymers lead to selective solvation of different families of carbon nanotubes. Furthermore, chemical screening of closely related polymers may pave the way toward simple, low-cost, and index-specific isolation of SWNTs.
Predicting wavelength-dependent photochemical reactivity and selectivity
Publisher: Springer Science and Business Media LLC
Date: 16-03-2021
DOI: 10.1038/S41467-021-21797-X
Abstract: Predicting the conversion and selectivity of a photochemical experiment is a conceptually different challenge compared to thermally induced reactivity. Photochemical transformations do not currently have the same level of generalized analytical treatment due to the nature of light interaction with a photoreactive substrate. Herein, we bridge this critical gap by introducing a framework for the quantitative prediction of the time-dependent progress of photoreactions via common LEDs. A wavelength and concentration dependent reaction quantum yield map of a model photoligation, i.e., the reaction of thioether o -methylbenzaldehydes via o -quinodimethanes with N -ethylmaleimide, is initially determined with a tunable laser system. Combined with experimental parameters, the data are employed to predict LED-light induced conversion through a wavelength-resolved numerical simulation. The model is validated with experiments at varied wavelengths. Importantly, a second algorithm allows the assessment of competing photoreactions and enables the facile design of λ -orthogonal ligation systems based on substituted o -methylbenzaldehydes.
Direct Access to Dithiobenzoate RAFT Agent Fragmentation Rate Coefficients by ESR Spin‐Trapping
Publisher: Wiley
Date: 30-10-2014
Abstract: The β-scission rate coefficient of tert-butyl radicals fragmenting off the intermediate resulting from their addition to tert-butyl dithiobenzoate-a reversible addition-fragmentation chain transfer (RAFT) agent-is estimated via the recently introduced electron spin resonance (ESR)-trapping methodology as a function of temperature. The newly introduced ESR-trapping methodology is critically evaluated and found to be reliable. At 20 °C, a fragmentation rate coefficient of close to 0.042 s(-1) is observed, whereas the activation parameters for the fragmentation reaction-determined for the first time-read EA = 82 ± 13.3 kJ mol(-1) and A = (1.4 ± 0.25) × 10(13) s(-1) . The ESR spin-trapping methodology thus efficiently probes the stability of the RAFT adduct radical under conditions relevant for the pre-equilibrium of the RAFT process. It particularly indicates that stable RAFT adduct radicals are indeed formed in early stages of the RAFT poly-merization, at least when dithiobenzoates are employed as controlling agents as stipulated by the so-called slow fragmentation theory. By design of the methodology, the obtained fragmentation rate coefficients represent an upper limit. The ESR spin-trapping methodology is thus seen as a suitable tool for evaluating the fragmentation rate coefficients of a wide range of RAFT adduct radicals.
Dynamic covalent single chain nanoparticles based on hetero Diels–Alder chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6CC07427H
Abstract: We report a dynamic covalent single chain nanoparticle collapse and subsequent re-opening of the coil based on hetero Diels–Alder chemistry.
Light-Gated Control of Conformational Changes in Polymer Brushes
Publisher: Wiley
Date: 10-07-2022
Abstract: Herein, a strategy to control conformational changes in grafted polymer brushes via photoinduced crosslinking of photoreactive groups embedded into the lateral architecture of a polymer brush is reported. Poly(methylmethacrylate)‐based polymer brushes containing UV‐light (λ = 325 nm) photoreactive o ‐methyl benzaldehyde moieties are synthesized using surface‐initiated reversible deactivation polymerization. The conformational changes in polymer brushes upon UV‐light triggered crosslinking are comprehensively analyzed through a full suite of surface sensitive characterization methods including time of flight secondary ion mass spectrometry, quartz crystal microbalance with dissipation monitoring, UV/vis spectroscopy, atomic force microscopy, nanoplasmonic sensing, and neutron reflectometry. The spatiotemporal control of the induced conformational changes is demonstrated via photolithography experiments. To enable an additional level of control, a second gate, the visible light (λ = 445 nm) active styrylpyrene moiety, is incorporated into the polymer brush architecture. Critically, wavelength‐selective crosslinking behavior is observed in the diblock copolymer structures allowing to crosslink specific sections of the lateral brush architecture as a function of irradiation wavelength.
Direct access to biocompatible nitroxide containing polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY00089A
Abstract: Ring-opening copolymerization of a nitroxide containing cyclic carbonate and d / l -lactide was used to directly access well-defined biocompatible polymers.
Photo-reversible bonding and cleavage of block copolymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY00843K
Abstract: We introduce a synthetic avenue for the completely photoreversible formation of block copolymers based on anthracene chemistry.
Radical addition fragmentation chain transfer (RAFT) polymerization of ferrocenyl (Meth)acrylates
Publisher: Wiley
Date: 28-09-2011
DOI: 10.1002/POLA.24994
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