ORCID Profile
0000-0001-9487-4689
Current Organisations
The University of Memphis
,
University of East Anglia Norwich Medical School
,
University of East Anglia
,
Karlsruher Institut für Technologie - Campus Nord
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Publications
Interplay of structural dynamics and electronic effects in an engineered assembly of pentacene in a metal–organic framework
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0SC07073D
Abstract: Pentacene assembled into 1D arrays using a metal–organic framework (MOF) approach. This cofacial packing motif, which is not present in pentacene bulk, shows an interesting interplay of band-like and hopping-type transport.
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.
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.
Method for accurate experimental determination of singlet and triplet exciton diffusion between thermally activated delayed fluorescence molecules
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0SC05190J
Abstract: A method for measuring triplet diffusion between TADF molecules is presented, and implications of limited triplet diffusion for OLEDs discussed.
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.
Disulfide‐Bridged Dynamic Covalent Triazine Polymer Thin Films by Interface Polymerization: High Refractive Index with Excellent Optical Transparency
Publisher: Wiley
Date: 24-08-2023
Abstract: Exploring innovative strategies for molecular structuring of dynamic materials that combine self‐correcting intrinsic reversibility with the robustness of covalent bonds, has been a long‐standing objective from applications perspective in fields ranging from molecular engineering to nanotechnology and interfacial science. To establish dynamic covalent chemistry approaches combined with interfacial polymerization, herein, a distinct synthetic approach is reported to develop disulfide‐bridged 2D polymeric C 3 N 3 S 3 triazine thin‐films by interfacial thiol‐disulfide dynamic exchange process crosslinking tritopic planar 1,3,5‐triazine‐2,4,6‐trithiol molecular tectons via intermolecular disulfide formation in the presence of I 2 vapors at the air/water interface under redox condition. The resulting centimeter‐scale polymeric thin‐films are covalently cross‐linked, dynamic in nature, featuring tunable thickness (6–200 nm) and significant morphological variations are realized under the influence of varying reaction time, concentration and types of reducing agents. Notably, C 3 N 3 S 3 polymer thin films exhibit a transflectance of around 99.5% in the range from 430 to 1800 nm, show high refractive indices (1.730–1.488) and optical anisotropy with uniaxial negative birefringence. The C 3 N 3 S 3 free‐standing polymer thin‐films can be easily transferred to different substrates or possibly into application‐relevant forms for device fabrications, making this useful from materials application perspective.
Fluorescent Nanozeolite Receptors for the Highly Selective and Sensitive Detection of Neurotransmitters in Water and Biofluids.
Publisher: Wiley
Date: 27-09-2021
Abstract: The design and preparation of synthetic binders (SBs) applicable for small biomolecule sensing in aqueous media remains very challenging. SBs designed by the lock-and-key principle can be selective for their target analyte but usually show an insufficient binding strength in water. In contrast, SBs based on symmetric macrocycles with a hydrophobic cavity can display high binding affinities but generally suffer from indiscriminate binding of many analytes. Herein, a completely new and modular receptor design strategy based on microporous hybrid materials is presented yielding zeolite-based artificial receptors (ZARs) which reversibly bind the neurotransmitters serotonin and dopamine with unprecedented affinity and selectivity even in saline biofluids. ZARs are thought to uniquely exploit both the non-classical hydrophobic effect and direct non-covalent recognition motifs, which is supported by in-depth photophysical, and calorimetric experiments combined with full atomistic modeling. ZARs are thermally and chemically robust and can be readily prepared at gram scales. Their applicability for the label-free monitoring of important enzymatic reactions, for (two-photon) fluorescence imaging, and for high-throughput diagnostics in biofluids is demonstrated. This study showcases that artificial receptor based on microporous hybrid materials can overcome standing limitations of synthetic chemosensors, paving the way towards personalized diagnostics and metabolomics.
Challenges and Opportunities in 3D Laser Printing Based on (1 + 1)-Photon Absorption
Publisher: American Chemical Society (ACS)
Date: 14-12-2022
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
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.
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.
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.
Contact spacing controls the on-current for all-carbon field effect transistors
Publisher: Springer Science and Business Media LLC
Date: 18-11-2021
DOI: 10.1038/S42005-021-00747-5
Abstract: All-carbon field-effect transistors, which combine carbon nanotubes and graphene hold great promise for many applications such as digital logic devices and single-photon emitters. However, the understanding of the physical properties of carbon nanotube (CNT)/graphene hybrid systems in such devices remained limited. In this combined experimental and theoretical study, we use a quantum transport model for field-effect transistors based on graphene electrodes and CNT channels to explain the experimentally observed low on currents. We find that large graphene/CNT spacing and short contact lengths limit the device performance. We have also elucidated in this work the experimentally observed ambipolar transport behavior caused by the flat conduction- and valence-bands and describe non-ideal gate-control of the contacts and channel region by the quantum capacitance of graphene and the carbon nanotube. We hope that our insights will accelerate the design of efficient all-carbon field-effect transistors.
Annual transition probabilities of overweight and obesity in older adults: Evidence from World Health Organization Study on global AGEing and adult health
Publisher: Elsevier BV
Date: 02-2020
Solid and Hollow Poly(p-xylylene) Particles Synthesis via Metal–Organic Framework-Templated Chemical Vapor Polymerization
Publisher: American Chemical Society (ACS)
Date: 14-07-2022
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.
Ionic liquid gating of single-walled carbon nanotube devices with ultra-short channel length down to 10 nm
Publisher: AIP Publishing
Date: 08-02-2021
DOI: 10.1063/5.0034792
Abstract: Ionic liquids enable efficient gating of materials with nanoscale morphology due to the formation of a nanoscale double layer that can also follow strongly vaulted surfaces. On carbon nanotubes, this can lead to the formation of a cylindrical gate layer, allowing an ideal control of the drain current even at small gate voltages. In this work, we apply ionic liquid gating to chirality-sorted (9, 8) carbon nanotubes bridging metallic electrodes with gap sizes of 20 nm and 10 nm. The single-tube devices exhibit diameter-normalized current densities of up to 2.57 mA/μm, on-off ratios up to 104, and a subthreshold swing down to 100 mV/dec. Measurements after long vacuum storage indicate that the hysteresis of ionic liquid gated devices depends not only on the gate voltage sweep rate and the polarization dynamics but also on charge traps in the vicinity of the carbon nanotube, which, in turn, might act as trap states for the ionic liquid ions. The ambipolar transfer characteristics are compared with calculations based on the Landauer–Büttiker formalism. Qualitative agreement is demonstrated, and the possible reasons for quantitative deviations and possible improvements to the model are discussed. Besides being of fundamental interest, the results have potential relevance for biosensing applications employing high-density device arrays.
Healthcare expenditure and its socio-demographic and clinical predictors in Australians with poorly controlled asthma
Publisher: Public Library of Science (PLoS)
Date: 05-01-2023
DOI: 10.1371/JOURNAL.PONE.0279748
Abstract: Asthma has substantial and increasing health and economic burden worldwide. This study aimed to estimate healthcare expenditure and determine the factors that increase expenditure in Australians with poorly controlled asthma. In iduals ≥18 years of age with poorly controlled asthma, as determined by a score ≥1.5 on the Asthma Control Questionnaire, were included in the study. Healthcare utilization costs from medical services and medications were estimated over an average follow-up of 12 months from administratively linked data: the Medicare Benefits Schedule and Pharmaceutical Benefits Scheme. A generalized linear model with gamma distribution and log link was used to predict participants’ key baseline characteristics associated with variations in healthcare costs. A total of 341 participants recruited through community pharmacies were included. The mean (standard deviation, SD) age of participants was 56.6 (SD 17.6) years, and approximately 71% were females. The adjusted average monthly healthcare expenditure per participant was $AU386 (95% CI: 336, 436). On top of the average monthly costs, an incremental expenditure was found for each year increase in age ($AU4 95% CI: 0.78, 7), being unemployed ($AU201 95% CI: 91, 311), one unit change in worsening quality of life ($AU35 95% CI: 9, 61) and being diagnosed with depression and anxiety ($AU171 95% CI: 36, 306). In a cohort of Australian patients, characterized by poor asthma control and co-morbidities in iduals impose substantial economic burden in terms of Medicare funded medical services and medications. Programs addressing strategies to improve the quality of life and manage co-morbid anxiety and depression and encourage asthma patients’ engagement in clinically tolerable jobs, may result in significant cost savings to the health system.
Related Organisations
University Of East Anglia Norwich Medical School
Location: United Kingdom of Great Britain and Northern Ireland
University Of East Anglia
Location: United Kingdom of Great Britain and Northern Ireland
Related Funding Activities
No related grants have been discovered for Wolfgang Wenzel.