ORCID Profile
0000-0003-0904-6630
Current Organisation
RMIT University
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Soft condensed matter | Computational chemistry | Colloid and surface chemistry | Physical Chemistry of Materials | Colloid and Surface Chemistry | Physical chemistry | Physical Chemistry (Incl. Structural)
Expanding Knowledge in the Chemical Sciences | Metals (e.g. Composites, Coatings, Bonding) |
Publisher: American Chemical Society (ACS)
Date: 12-04-2021
Publisher: Wiley
Date: 26-02-2202
Publisher: American Chemical Society (ACS)
Date: 19-09-2022
Abstract: Nanomaterials have the potential to transform biological and biomedical research, with applications ranging from drug delivery and diagnostics to targeted interference of specific biological processes. Most existing research is aimed at developing nanomaterials for specific tasks such as enhanced biocellular internalization. However, fundamental aspects of the interactions between nanomaterials and biological systems, in particular, membranes, remain poorly understood. In this study, we provide detailed insights into the molecular mechanisms governing the interaction and evolution of one of the most common synthetic nanomaterials in contact with model phospholipid membranes. Using a combination of atomic force microscopy (AFM) and molecular dynamics (MD) simulations, we elucidate the precise mechanisms by which citrate-capped 5 nm gold nanoparticles (AuNPs) interact with supported lipid bilayers (SLBs) of pure fluid (DOPC) and pure gel-phase (DPPC) phospholipids. On fluid-phase DOPC membranes, the AuNPs adsorb and are progressively internalized as the citrate capping of the NPs is displaced by the surrounding lipids. AuNPs also interact with gel-phase DPPC membranes where they partially embed into the outer leaflet, locally disturbing the lipid organization. In both systems, the AuNPs cause holistic perturbations throughout the bilayers. AFM shows that the lateral diffusion of the particles is several orders of magnitude smaller than that of the lipid molecules, which creates some temporary scarring of the membrane surface. Our results reveal how functionalized AuNPs interact with differing biological membranes with mechanisms that could also have implications for cooperative membrane effects with other molecules.
Publisher: AIP Publishing
Date: 18-04-2022
DOI: 10.1063/5.0085592
Abstract: Ionic liquids (ILs) are well classified as designer solvents based on the ease of tailoring their properties through modifying the chemical structure of the cation and anion. However, while many structure–property relationships have been developed, these generally only identify the most dominant trends. Here, we have used machine learning on existing experimental data to construct robust models to produce meaningful predictions across a broad range of cation and anion chemical structures. Specifically, we used previously collated experimental data for the viscosity and conductivity of protic ILs [T. L. Greaves and C. J. Drummond, Chem. Rev. 115, 11379–11448 (2015)] as the inputs for multiple linear regression and neural network models. These were then used to predict the properties of all 1827 possible cation–anion combinations (excluding the input combinations). These models included the effect of water content of up to 5 wt. %. A selection of ten new protic ILs was then prepared, which validated the usefulness of the models. Overall, this work shows that relatively sparse data can be used productively to predict physicochemical properties of vast arrays of ILs.
Publisher: Wiley
Date: 25-01-2023
Abstract: Ionic liquids (ILs) are a widely investigated class of solvents for scientific and industrial applications due to their desirable and “tunable” properties. The IL–solid interface is a complex entity, and despite intensive investigation, its true nature remains elusive. The understanding of the IL–solid interface has evolved over the last decade from a simple 1D double layer, to a 2D ordered interface, and finally a liquid‐specific, complex 3D ordered liquid interface. However, most studies depend solely on one technique, which often only examine one aspect of the interfacial nanostructure. Here, a holistic study of the protic IL–solid interface is presented, which provides a more detailed picture of IL interfacial solvation. The 3D nanostructure of the ethylammonium nitrate (EAN)–mica interface is investigated using a combination of 1D, 2D, and 3D litude modulated‐atomic force microscopy and molecular dynamics simulations. Importantly, it is found that the EAN–mica interface is more complex than previously reported, possessing surface‐adsorbed, near‐surface, surface‐normal, and lateral heterogeneity, which propagates at relatively large distances from the solid substrate. The work presented in this study meaningfully enhances the understanding of the IL–solid interface.
Publisher: IEEE
Date: 02-2014
Publisher: American Chemical Society (ACS)
Date: 17-08-2022
Abstract: Mixtures of short-chain alcohols and water produce anomalous thermodynamic and structural quantities, including molecular segregation into water-rich and alcohol-rich components. Herein, we used molecular dynamics simulations with polarizable models to investigate interactions that could drive the self-association of water molecules in mixtures with methanol (MeOH). As water was diluted with MeOH, significant changes in the distribution of molecules and solvation properties occurred, where water exhibited a clear preference for self-association. When common structural quantities were analyzed, it was found that there was a clear reduction in water-water hydrogen bonding and tetrahedral order (both in terms of typical bulk behavior), contrary to the observed water self-association. However, when dipolar dispersion forces between all molecules as a function of system composition were analyzed, it was found that water-water dipolar interactions became significantly stronger with dilution (6-fold stronger interaction in 75% MeOH compared to 0% MeOH). This was only observed for water, where MeOH-MeOH interactions became weaker as the systems were more dilute in MeOH. These forces result from specific dipole orientations, likely occurring to adopt lower energy configurations (i.e., head-to-tail or antiparallel). For water, this may result from lost other interactions (e.g., hydrogen bonding), leading to more rotational freedom between the dipole moments. These intriguing changes in dipolar interactions, which directly result from structural changes, can therefore explain, in part, the driving force for water self-association in MeOH-water mixtures.
Publisher: American Chemical Society (ACS)
Date: 29-08-2018
Abstract: Peptide self-assembly represents a powerful bottom-up approach to the fabrication of nanomaterials. β
Publisher: Springer Science and Business Media LLC
Date: 10-03-2022
DOI: 10.1038/S41467-022-28869-6
Abstract: Catalytic solvent regeneration has attracted broad interest owing to its potential to reduce energy consumption in CO 2 separation, enabling industry to achieve emission reduction targets of the Paris Climate Accord. Despite recent advances, the development of engineered acidic nanocatalysts with unique characteristics remains a challenge. Herein, we establish a strategy to tailor the physicochemical properties of metal-organic frameworks (MOFs) for the synthesis of water-dispersible core-shell nanocatalysts with ease of use. We demonstrate that functionalized nanoclusters (Fe 3 O 4 -COOH) effectively induce missing-linker deficiencies and fabricate mesoporosity during the self-assembly of MOFs. Superacid sites are created by introducing chelating sulfates on the uncoordinated metal clusters, providing high proton donation capability. The obtained nanomaterials drastically reduce the energy consumption of CO 2 capture by 44.7% using only 0.1 wt.% nanocatalyst, which is a ∽10-fold improvement in efficiency compared to heterogeneous catalysts. This research represents a new avenue for the next generation of advanced nanomaterials in catalytic solvent regeneration.
Publisher: International Union of Crystallography (IUCr)
Date: 21-03-2022
DOI: 10.1107/S1600577522001862
Abstract: Serial crystallography of membrane proteins often employs high-viscosity injectors (HVIs) to deliver micrometre-sized crystals to the X-ray beam. Typically, the carrier medium is a lipidic cubic phase (LCP) media, which can also be used to nucleate and grow the crystals. However, despite the fact that the LCP is widely used with HVIs, the potential impact of the injection process on the LCP structure has not been reported and hence is not yet well understood. The self-assembled structure of the LCP can be affected by pressure, dehydration and temperature changes, all of which occur during continuous flow injection. These changes to the LCP structure may in turn impact the results of X-ray diffraction measurements from membrane protein crystals. To investigate the influence of HVIs on the structure of the LCP we conducted a study of the phase changes in monoolein/water and monoolein/buffer mixtures during continuous flow injection, at both atmospheric pressure and under vacuum. The reservoir pressure in the HVI was tracked to determine if there is any correlation with the phase behaviour of the LCP. The results indicated that, even though the reservoir pressure underwent (at times) significant variation, this did not appear to correlate with observed phase changes in the s le stream or correspond to shifts in the LCP lattice parameter. During vacuum injection, there was a three-way coexistence of the gyroid cubic phase, diamond cubic phase and lamellar phase. During injection at atmospheric pressure, the coexistence of a cubic phase and lamellar phase in the monoolein/water mixtures was also observed. The degree to which the lamellar phase is formed was found to be strongly dependent on the co-flowing gas conditions used to stabilize the LCP stream. A combination of laboratory-based optical polarization microscopy and simulation studies was used to investigate these observations.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Springer Science and Business Media LLC
Date: 06-06-2022
DOI: 10.1038/S41557-022-00965-6
Abstract: Insights into metal-matrix interactions in atomically dispersed catalytic systems are necessary to exploit the true catalytic activity of isolated metal atoms. Distinct from catalytic atoms spatially separated but immobile in a solid matrix, here we demonstrate that a trace amount of platinum naturally dissolved in liquid gallium can drive a range of catalytic reactions with enhanced kinetics at low temperature (318 to 343 K). Molecular simulations provide evidence that the platinum atoms remain in a liquid state in the gallium matrix without atomic segregation and activate the surrounding gallium atoms for catalysis. When used for electrochemical methanol oxidation, the surface platinum atoms in the gallium-platinum system exhibit an activity of [Formula: see text] three orders of magnitude higher than existing solid platinum catalysts. Such a liquid catalyst system, with a dynamic interface, sets a foundation for future exploration of high-throughput catalysis.
Publisher: Elsevier
Date: 2024
Publisher: American Chemical Society (ACS)
Date: 08-09-2014
DOI: 10.1021/JP5060974
Abstract: Understanding, and improving, the behavior of thin surface films under exposure to externally applied forces is important for applications such as mimicking biological membranes, water evaporation mitigation, and recovery of oil spills. This paper demonstrates that the incorporation of a water-soluble polymer into the surface film composition, i.e., formation of a three-duolayer system, shows improved performance under an applied dynamic stress, with an evaporation saving of 84% observed after 16 h, compared to 74% for the insoluble three-monolayer alone. Canal viscometry and spreading rate experiments, performed using the same conditions, demonstrated an increased surface viscosity and faster spreading rate for the three-duolayer system, likely contributing to the observed improvement in dynamic performance. Brewster angle microscopy and dye-tagged polymers were used to visualize the system and demonstrated that the duolayer and monolayer system both form a homogeneous film of uniform, single-molecule thickness, with the excess material compacting into small floating reservoirs on the surface. It was also observed that both components have to be applied to the water surface together in order to achieve improved performance under dynamic conditions. These findings have important implications for the use of surface films in various applications where resistance to external disturbance is required.
Publisher: Wiley
Date: 23-03-2016
Abstract: Gold nanoparticles (AuNPs) are an integral part of many exciting and novel biomedical applications, sparking the urgent need for a thorough understanding of the physicochemical interactions occurring between these inorganic materials, their functional layers, and the biological species they interact with. Computational approaches are instrumental in providing the necessary molecular insight into the structural and dynamic behavior of the Au-bio interface with spatial and temporal resolutions not yet achievable in the laboratory, and are able to facilitate a rational approach to AuNP design for specific applications. A perspective of the current successes and challenges associated with the multiscale computational treatment of Au-bio interfacial systems, from electronic structure calculations to force field methods, is provided to illustrate the links between different approaches and their relationship to experiment and applications.
Publisher: American Chemical Society (ACS)
Date: 13-03-2026
Publisher: American Chemical Society (ACS)
Date: 11-11-2013
DOI: 10.1021/LA402275P
Abstract: All-atom molecular dynamics simulations and experimental characterization have been used to examine the structure and dynamics of novel evaporation-suppressing films where the addition of a water-soluble polymer to an ethylene glycol monooctadecyl ether monolayer leads to improved water evaporation resistance. Simulations and Langmuir trough experiments demonstrate the surface activity of poly(vinyl pyrrolidone) (PVP). Subsequent MD simulations performed on the thin films supported by the PVP sublayer show that, at low surface pressures, the polymer tends to concentrate at the film/water interface. The simulated atomic concentration profiles, hydrogen bonding patterns, and mobility analyses of the water-polymer-monolayer interfaces reveal that the presence of PVP increases the atomic density near the monolayer film, improves the film stability, and reduces the mobility of interfacial waters. These observations explain the molecular basis of the improved efficacy of these monolayer olymer systems for evaporation protection of water and can be used to guide future development of organic thin films for other applications.
Publisher: Springer Science and Business Media LLC
Date: 03-02-2022
Publisher: American Chemical Society (ACS)
Date: 25-06-2021
DOI: 10.1021/JACS.1C04396
Publisher: American Chemical Society (ACS)
Date: 06-07-2021
DOI: 10.26434/CHEMRXIV-2021-0DT3N
Abstract: Water is a unique solvent that is ubiquitous in biology and present in a variety of solutions, mixtures, and materials settings. It therefore forms the basis for all molecular dynamics simulations of biological phenomena, as well as for many chemical, industrial, and materials investigations. Over the years, many water models have been developed, and it remains a challenge to find a single water model that accurately reproduces all experimental properties of water simultaneously. Here, we report a comprehensive comparison of structural and dynamic properties of 30 commonly used 3-point, 4-point, 5-point, and polarizable water models simulated using consistent settings and analysis methods. For the properties of density, coordination number, surface tension, dielectric constant, self-diffusion coefficient, and solvation free energy of methane, models published within the past two decades consistently show better agreement with experimental values compared to models published earlier, albeit with some notable exceptions. However, no single model reproduced all experimental values exactly, highlighting the need to carefully choose a water model for a particular study, depending on the phenomena of interest. Finally, machine learning algorithms quantified the relationship between the water model force field parameters and the resulting bulk properties, providing insight into the parameter-property relationship and illustrating the challenges of developing a water model that can accurately reproduce all properties of water simultaneously.
Publisher: Wiley
Date: 17-06-2021
Abstract: Polymer brush surfaces that alter their physical properties in response to chemical stimuli have the capacity to be used as new surface‐based sensing materials. For such surfaces, detecting the polymer conformation is key to their sensing capabilities. Herein, we report on FRET‐integrated ultrathin ( nm) polymer brush surfaces that exhibit stimuli‐dependent FRET with changing brush conformation. Poly( N ‐isopropylacrylamide) polymers were chosen due their exceptional sensitivity to liquid mixture compositions and their ability to be assembled into well‐defined polymer brushes. The brush transitions were used to optically sense changes in liquid mixture compositions with high spatial resolution (tens of micrometers), where the FRET coupling allowed for noninvasive observation of brush transitions around complex interfaces with real‐time sensing of the liquid environment. Our methods have the potential to be leveraged towards greater surface‐based sensing capabilities at intricate interfaces.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 09-04-2021
Abstract: Aggregation-induced through-space charge transfer can be used to tune single-fluorophore emission in simple polymer systems.
Publisher: Springer New York
Date: 24-11-2011
DOI: 10.1007/978-1-61779-465-0_13
Abstract: Structure-based virtual screening is a useful computational technique for ligand discovery. To systematically evaluate different docking approaches, it is important to have a consistent benchmarking protocol that is both relevant and unbiased. Here, we describe the designing of a benchmarking data set for docking screen assessment, a standard docking screening process, and the analysis and presentation of the enrichment of annotated ligands among a background decoy database.
Publisher: AIP Publishing
Date: 13-08-2020
DOI: 10.1063/5.0013634
Abstract: Perylene diimide (PDI) derivatives are widely used materials for luminescent solar concentrator (LSC) applications due to their attractive optical and electronic properties. In this work, we study aggregation-induced exciton quenching pathways in four PDI derivatives with increasing steric bulk, which were previously synthesized. We combine molecular dynamics and quantum chemical methods to simulate the aggregation behavior of chromophores at low concentration and compute their excited state properties. We found that PDIs with small steric bulk are prone to aggregate in a solid state matrix, while those with large steric volume displayed greater tendencies to isolate themselves. We find that for the aggregation class of PDI dimers, the optically accessible excitations are in close energetic proximity to triplet charge transfer (CT) states, thus facilitating inter-system crossing and reducing overall LSC performance. While direct singlet fission pathways appear endothermic, evidence is found for the facilitation of a singlet fission pathway via intermediate CT states. Conversely, the insulation class of PDI does not suffer from aggregation-induced photoluminescence quenching at the concentrations studied here and therefore display high photon output. These findings should aid in the choice of PDI derivatives for various solar applications and suggest further avenues for functionalization and study.
Publisher: Wiley
Date: 31-01-2022
Abstract: Liquid metals (LMs) have emerged as novel materials for biomedical applications. Here, the interactions taking place between cells and LMs are reported, presenting a unique opportunity to explore and understand the LM‐biological interface. Several high‐resolution imaging techniques are used to characterize the interaction between droplets of gallium LM and bacterial, fungal, and mammalian cells. Adhesive interactions between cells and LM droplets are observed, causing deformation of the LM droplet surface, resulting in surface wrinkling and in some cases, breakage of the native oxide layer present on the LM droplet surface. In many instances, the cell wall deforms to intimately contact the LM droplets. Single‐cell force spectroscopy is performed to quantify the adhesion forces between cells and LM and characterize the nature of the adhesion. It is proposed that the flexible nature of the cell enables multiple adhesion sites with the LM droplets, imparting tensile forces on the LM droplet surface, which results in surface wrinkling on the LM droplets due to their liquid nature. Molecular dynamics simulations also suggest that flexible biomolecules on the cell surface can disrupt the Ga 2 O 3 layer formed at the LM droplet surface. This study reveals a unique biointerfacial interaction and provides insights into the mechanisms involved.
Publisher: Wiley
Date: 13-07-2022
Abstract: Nitroreductases activate nitroaromatic antibiotics and cancer prodrugs to cytotoxic hydroxylamines and reduce quinones to quinols. Using steady-state and stopped-flow kinetics, we show that the Escherichia coli nitroreductase NfsA is 20-50 fold more active with NADPH than with NADH and that product release may be rate-limiting. The crystal structure of NfsA with NADP
Publisher: American Chemical Society (ACS)
Date: 03-08-2011
DOI: 10.1021/JP204204X
Abstract: The introduction of selenium into DNA in the place of oxygen provides a unique opportunity for studying the fidelity of DNA replication, as well as providing advantages in the growth of DNA crystals and the greater resolution of their structures. However, the atomic mechanisms of the relative stability and base pair recognition of the selenium-modified DNA are poorly understood. In the present study, quantum mechanics calculations were performed on base pairings, base stacking, and base-water interactions for both unmodified thymine and thymine with the 2-exo-oxygen replaced with selenium, and the results were used to develop and validate CHARMM force field parameters for the 2-Se-thymine. Subsequently, molecular dynamics simulations and free-energy perturbation calculations were performed on 11-base DNA sequences containing native thymine and the 2-Se-thymine. The calculated relative free-energy values are in good agreement with experimentally determined relative stability, where the 2-Se-thymine offers similar stability to T-A in cognate DNA, while it dramatically destabilizes the DNA containing the T-G mismatch base pair when 2-Se-thymine is incorporated. Thus, 2-Se-thymine largely increases the native T-A base pair fidelity by discouraging the T-G wobble pair. Insights into the high pairing specificity and the relative stability of selenium-modified DNA were obtained based on detailed structural and energetic analysis of molecular dynamics trajectories. Our studies move one step further toward an understanding of the high base pair fidelity and thermodynamic properties of Se-DNA in solution and in protein-DNA complexes.
Publisher: American Chemical Society (ACS)
Date: 24-04-2023
Publisher: Springer Science and Business Media LLC
Date: 23-06-2021
DOI: 10.1038/S41467-021-23278-7
Abstract: A major health concern of the 21 st century is the rise of multi-drug resistant pathogenic microbial species. Recent technological advancements have led to considerable opportunities for low-dimensional materials (LDMs) as potential next-generation antimicrobials. LDMs have demonstrated antimicrobial behaviour towards a variety of pathogenic bacterial and fungal cells, due to their unique physicochemical properties. This review provides a critical assessment of current LDMs that have exhibited antimicrobial behaviour and their mechanism of action. Future design considerations and constraints in deploying LDMs for antimicrobial applications are discussed. It is envisioned that this review will guide future design parameters for LDM-based antimicrobial applications.
Publisher: Wiley
Date: 26-03-2023
Abstract: Although sonodynamic therapy (SDT) has shown promise for cancer treatment, the lack of efficient sonosensitizers (SSs) has limited the clinical application of SDT. Here, a new strategy is reported for designing efficient nano‐sonosensitizers based on 2D nanoscale metal–organic layers (MOLs). Composed of Hf‐oxo secondary building units (SBUs) and iridium‐based linkers, the MOL is anchored with 5,10,15,20‐tetra( p ‐benzoato)porphyrin (TBP) sensitizers on the SBUs to afford TBP@MOL. TBP@MOL shows 14.1‐ and 7.4‐fold higher singlet oxygen ( 1 O 2 ) generation than free TBP ligands and Hf‐TBP, a 3D nanoscale metal–organic framework, respectively. The 1 O 2 generation of TBP@MOL is enhanced by isolating TBP SSs on the SBUs of the MOL, which prevents aggregation‐induced quenching of the excited sensitizers, and by triplet–triplet Dexter energy transfer between excited iridium‐based linkers and TBP SSs, which more efficiently harnesses broad‐spectrum sonoluminescence. Anchoring TBP on the MOL surface also enhances the energy transfer between the excited sensitizer and ground‐state triplet oxygen to increase 1 O 2 generation efficacy. In mouse models of colorectal and breast cancer, TBP@MOL demonstrates significantly higher SDT efficacy than Hf‐TBP and TBP. This work uncovers a new strategy to design effective nano‐sonosensitizers by facilitating energy transfer to efficiently capture broad‐spectrum sonoluminescence and enhance 1 O 2 generation.
Publisher: American Chemical Society (ACS)
Date: 18-08-2021
Publisher: Wiley
Date: 12-09-2021
Abstract: The introduction of trace impurities within the doping processes of semiconductors is still a technological challenge for the electronics industries. By taking advantage of the selective enrichment of liquid metal interfaces, and harvesting the doped metal oxide semiconductor layers, the complexity of the process can be mitigated and a high degree of control over the outcomes can be achieved. Here, a mechanism of natural filtering for the preparation of doped 2D semiconducting sheets based on the different migration tendencies of metallic elements in the bulk competing for enriching the interfaces is proposed. As a model, liquid metal alloys with different weight ratios of Sn and Bi in the bulk are employed for harvesting Bi 2 O 3 ‐doped SnO nanosheets. In this model, Sn shows a much stronger tendency than Bi to occupy surface sites of the Bi–Sn alloys, even at the very high concentrations of Bi in the bulk. This provides the opportunity for creating SnO 2D sheets with tightly controlled Bi 2 O 3 dopants. By way of ex le, it is demonstrated how such nanosheets could be made selective to both reducing and oxidizing environmental gases. The process demonstrated here offers significant opportunities for future synthesis and fabrication processes in the electronics industries.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8NR09221D
Abstract: Cobalt–tannic acid-coated gold nanoparticles are found to better inhibit amyloid fibril formation than other metal-based tannic acid-coated particles.
Publisher: Elsevier BV
Date: 2024
Publisher: MDPI AG
Date: 22-03-2023
DOI: 10.3390/IJMS24065987
Abstract: Escherichia coli NfsB has been studied extensively for its potential for cancer gene therapy by reducing the prodrug CB1954 to a cytotoxic derivative. We have previously made several mutants with enhanced activity for the prodrug and characterised their activity in vitro and in vivo. Here, we determine the X-ray structure of our most active triple and double mutants to date, T41Q/N71S/F124T and T41L/N71S. The two mutant proteins have lower redox potentials than wild-type NfsB, and the mutations have lowered activity with NADH so that, in contrast to the wild-type enzyme, the reduction of the enzyme by NADH, rather than the reaction with CB1954, has a slower maximum rate. The structure of the triple mutant shows the interaction between Q41 and T124, explaining the synergy between these two mutations. Based on these structures, we selected mutants with even higher activity. The most active one contains T41Q/N71S/F124T/M127V, in which the additional M127V mutation enlarges a small channel to the active site. Molecular dynamics simulations show that the mutations or reduction of the FMN cofactors of the protein has little effect on its dynamics and that the largest backbone fluctuations occur at residues that flank the active site, contributing towards its broad substrate range.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1TB02575A
Abstract: Black phosphorus (BP) nanoflakes have shown high antimicrobial activity. The interaction of microbial cells and black phosphorus nanoflakes was investigated using microscopic techniques and synchrotron source ATR-FTIR spectroscopy.
Publisher: Wiley
Date: 06-04-2020
Publisher: Elsevier
Date: 2012
Publisher: Elsevier BV
Date: 04-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TB01655A
Abstract: Broad-spectrum treatment of monoculture and mixed species biofilms using magnetically actuated, liquid metal particles.
Publisher: American Chemical Society (ACS)
Date: 06-10-2015
Publisher: Cambridge University Press (CUP)
Date: 06-07-2021
DOI: 10.33774/CHEMRXIV-2021-0DT3N
Abstract: Water is a unique solvent that is ubiquitous in biology and present in a variety of solutions, mixtures, and materials settings. It therefore forms the basis for all molecular dynamics simulations of biological phenomena, as well as for many chemical, industrial, and materials investigations. Over the years, many water models have been developed, and it remains a challenge to find a single water model that accurately reproduces all experimental properties of water simultaneously. Here, we report a comprehensive comparison of structural and dynamic properties of 30 commonly used 3-point, 4-point, 5-point, and polarizable water models simulated using consistent settings and analysis methods. For the properties of density, coordination number, surface tension, dielectric constant, self-diffusion coefficient, and solvation free energy of methane, models published within the past two decades consistently show better agreement with experimental values compared to models published earlier, albeit with some notable exceptions. However, no single model reproduced all experimental values exactly, highlighting the need to carefully choose a water model for a particular study, depending on the phenomena of interest. Finally, machine learning algorithms quantified the relationship between the water model force field parameters and the resulting bulk properties, providing insight into the parameter-property relationship and illustrating the challenges of developing a water model that can accurately reproduce all properties of water simultaneously.
Publisher: American Chemical Society (ACS)
Date: 04-09-2014
DOI: 10.1021/JP506098D
Abstract: The novel duolayer system, comprising a monolayer of ethylene glycol monooctadecyl ether (C18E1) and the water-soluble polymer poly(vinylpyrrolidone) (PVP), has been shown to resist forces such as wind stress to a greater degree than the C18E1 monolayer alone. This paper reports all-atom molecular dynamics simulations comparing the monolayer (C18E1 alone) and duolayer systems under an applied force parallel to the air/water interface. The simulations show that, due to the presence of PVP at the interface, the duolayer film exhibits an increase in chain tilt, ordering, and density, as well as a lower lateral velocity compared to the monolayer. These results provide a molecular rationale for the improved performance of the duolayer system under wind conditions, as well as an atomic-level explanation for the observed efficacy of the duolayer system as an evaporation suppressant, which may serve as a useful guide for future development for thin films where resistance to external perturbation is desirable.
Publisher: American Chemical Society (ACS)
Date: 22-03-2013
DOI: 10.1021/JP401027C
Abstract: Mixed monolayers of 1-octadecanol (C18OH) and ethylene glycol monooctadecyl ether (C18E1) were studied to assess their evaporation suppressing performance. An unexpected increase in performance and stability was found around the 0.5:0.5 bicomponent mixture and has been ascribed to a synergistic effect of the monolayers. Molecular dynamics simulations have attributed this to an additional hydrogen bonding interaction between the monolayer and water, due to the exposed ether oxygen of C18E1 in the mixed system compared to the same ether oxygen in the pure C18E1 system. This interaction is maximized around the 0.5:0.5 ratio due to the particular interfacial geometry associated with this mixture.
Publisher: Wiley
Date: 30-07-2023
Abstract: Organic–inorganic perovskite solar cells (PSCs) are promising candidates for next‐generation, inexpensive solar panels due to their commercially competitive cost and high power conversion efficiencies. However, PSCs suffer from poor stability. A new and vast subset of PSCs, quasi‐two‐dimensional Ruddlesden–Popper PSCs (quasi‐2D RP PSCs), has improved photostability and superior resilience to environmental conditions compared to three‐dimensional metal‐halide PSCs. To accelerate the search for new quasi‐2D RP PSCs, this work reports a combinatorial, machine learning (ML) enhanced high‐throughput perovskite film fabrication and optimization study. This work designs a bespoke experimental strategy and produces perovskite films with a range of different compositions using only spin‐coating free, reproducible robotic fabrication processes. The performance and characterization data of these solar cells are used to train a ML model that allow materials parameters to be optimized and direct the design of improved materials. The new, ML‐optimized, drop‐cast quasi‐2D RP perovskite films yield solar cells with power conversion efficiencies of up to 16.9%.
Publisher: American Chemical Society (ACS)
Date: 04-04-2022
DOI: 10.1021/ACS.LANGMUIR.1C03390
Abstract: Ionic liquids are versatile solvents that can be tailored through modification of the cation and anion species. Relatively little is known about the corrosive properties of protic ionic liquids. In this study, we have explored the corrosion of both zinc and copper within a series of protic ionic liquids consisting of alkylammonium or alkanolammonium cations paired with nitrate or carboxylate anions along with three aprotic imidazolium ionic liquids for comparison. Electrochemical studies revealed that the presence of either carboxylate anions or alkanolammonium cations tend to induce a cathodic shift in the corrosion potential. The effect in copper was similar in magnitude for both cations and anions, while the anion effect was slightly more pronounced than that of the cation in the case of zinc. For copper, the presence of carboxylate anions or alkanolammonium cations led to a notable decrease in corrosion current, whereas an increase was typically observed for zinc. The ionic liquid-metal surface interactions were further explored for select protic ionic liquids on copper using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) to characterize the interface. From these studies, the oxide species formed on the surface were identified, and copper speciation at the surface linked to ionic liquid and potential dependent surface passivation. Density functional theory and ab initio molecular dynamics simulations revealed that the ethanolammonium cation was more strongly bound to the copper surface than the ethylammonium counterpart. In addition, the nitrate anion was more tightly bound than the formate anion. These likely lead to competing effects on the process of corrosion: the tightly bound cations act as a source of passivation, whereas the tightly bound anions facilitate the electrodissolution of the copper.
Publisher: American Chemical Society (ACS)
Date: 10-03-2020
Publisher: Springer Science and Business Media LLC
Date: 18-01-2021
DOI: 10.1038/S41565-020-00835-7
Abstract: It is well-understood that during the liquid-to-solid phase transition of alloys, elements segregate in the bulk phase with the formation of microstructures. In contrast, we show here that in a Bi-Ga alloy system, highly ordered nanopatterns emerge preferentially at the alloy surfaces during solidification. We observed a variety of transition, hybrid and crystal-defect-like patterns, in addition to lamellar and rod-like structures. Combining experiments and molecular dynamics simulations, we investigated the influence of the superficial Bi and Ga
Publisher: American Chemical Society (ACS)
Date: 20-11-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CP00201A
Abstract: In this study, we have investigated the solvation properties of binary mixtures of PILs with molecular solvents. The selected binary solvent systems are the PILs ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) combined with either water, methanol, acetonitrile or DMSO.
Publisher: American Diabetes Association
Date: 06-2022
DOI: 10.2337/DB22-583-P
Abstract: Background: Use of open-source automated insulin delivery (AID) is associated with improved psychosocial outcomes among people with type 1 diabetes (T1D) . However, research to date has been qualitative or used study-specific single items. There is a need for quantitative research using validated measures in larger s les. Method: We conducted an international online survey to examine the psychosocial outcomes of open-source AID users and non-users. Validated questionnaires assessed diabetes-specific quality of life (QoL) , impact of the COVID-pandemic on diabetes-specific QoL, diabetes specific-positive well-being, diabetes treatment satisfaction, diabetes distress, fear of hypoglycaemia, general emotional well-being, and subjective sleep quality. Results: 587 participants completed at least one questionnaire, including 447 adults using open-source AID (mean age 43, 42% women) and 140 non-users (mean age 40, 64% women) . Table 1 shows significant between-group differences for all questionnaire scores. Discussion: Adults with T1D using open-source AID report significantly better psychosocial outcomes than non-users. Due to the cross-sectional design of this study, we cannot make any causal inferences about the use of these devices. Further research is needed to examine the reasons for these differences. J.Schipp: None. T.C.Skinner: None. J.Speight: Advisory Panel Insulet Corporation, Research Support Novo Nordisk, Sanofi. C.Hendrieckx: None. K.Braune: None. S.O'donnell: None. H.Ballhausen: None. B.Cleal: None. M.Wäldchen: None. C.Knoll: None. K.A.Gajewska: None. European Commission Horizon 2020 (823902)
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TB00573E
Abstract: A deep eutectic solvent is an effective cryoprotective agent for several human cell lines.
Publisher: American Chemical Society (ACS)
Date: 22-08-2018
Abstract: Using molecular dynamics simulations we probe the structure and interactions at the water liquid-vapor (LV) interface. In the interfacial region, strong ordering of dipole moments is observed, where water molecules exhibit "frustrated" orientations. By selectively analyzing the dipolar potential of mean force between these frustrated molecules and other molecules, we find a significant enhancement of dipolar interactions across the interfacial region. This interaction is derived in terms of a component of the surface tension, with a temperature-dependent magnitude of ∼-20 mN m
Publisher: No publisher found
Date: 2023
Publisher: Springer Science and Business Media LLC
Date: 17-01-2020
DOI: 10.1007/S00894-020-4288-9
Abstract: Nitroreductase enzymes are of interest as antibiotic targets and as activators in enzyme prodrug therapy, but the precise substrate binding orientation and reaction mechanism are poorly understood. In order to design more effective antibiotics and improve enzyme prodrug therapy, an atomistic description of nitroaromatic substrate binding in the active Michaelis complex is highly desirable. Here, using an iterative molecular dynamics (MD) simulation protocol, the binding of p-nitrobenzoic acid (p-NBA) in oxidized and reduced Enterobacter cloacae nitroreductase (NR) was investigated. For the oxidized NR, the MD simulations distinguished between the two possible binding orientations of p-NBA in NR from X-ray crystal structure data. For the reduced NR, a distinct active binding orientation of p-NBA was found when the second active site of the NR homodimer was occupied by a NADH analogue. This model of the active Michaelis complex of p-NBA with NR provides a rationale for the reduction of p-NBA by NR via a hydride transfer reaction mechanism suggested by experimental results, and brings the proposed reaction mechanism from experiment and computational models into agreement.
Publisher: American Chemical Society (ACS)
Date: 12-09-2022
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.JCIS.2021.10.163
Abstract: Deep eutectic solvents (DESs) are a tailorable class of solvents that are rapidly gaining scientific and industrial interest. This is because they are distinct from conventional molecular solvents, inherently tuneable via careful selection of constituents, and possess many attractive properties for applications, including catalysis, chemical extraction, reaction media, novel lubricants, materials chemistry, and electrochemistry. DESs are a class of solvents composed solely of hydrogen bond donors and acceptors with a melting point lower than the in idual components and are often fluidic at room temperature. A unique feature of DESs is that they possess distinct bulk liquid and interfacial nanostructure, which results from intra- and inter-molecular interactions, including coulomb forces, hydrogen bonding, van der Waals interactions, electrostatics, dispersion forces, and apolar-polar segregation. This nanostructure manifests as preferential spatial arrangements of the different species, and exists over several length scales, from molecular- to nano- and meso-scales. The physicochemical properties of DESs are dictated by structure-property relationships however, there is a significant gap in our understanding of the underlying factors which govern their solvent properties. This is a major limitation of DES-based technologies, as nanostructure can significantly influence physical properties and thus potential applications. This perspective provides an overview of the current state of knowledge of DES nanostructure, both in the bulk liquid and at solid interfaces. We provide definitions which clearly distinguish DESs as a unique solvent class, rather than a subset of ILs. An appraisal of recent work provides hints towards trends in structure-property relationships, while also highlighting inconsistencies within the literature suggesting new research directions for the field. It is hoped that this review will provide insight into DES nanostructure, their potential applications, and development of a robust framework for systematic investigation moving forward.
Publisher: Portland Press Ltd.
Date: 09-07-2021
DOI: 10.1042/BCJ20210160
Abstract: NfsA is a dimeric flavoprotein that catalyses the reduction in nitroaromatics and quinones by NADPH. This reduction is required for the activity of nitrofuran antibiotics. The crystal structure of free Escherichia coli NfsA and several homologues have been determined previously, but there is no structure of the enzyme with ligands. We present here crystal structures of oxidised E. coli NfsA in the presence of several ligands, including the antibiotic nitrofurantoin. Nitrofurantoin binds with the furan ring, rather than the nitro group that is reduced, near the N5 of the FMN. Molecular dynamics simulations show that this orientation is only favourable in the oxidised enzyme, while potentiometry suggests that little semiquinone is formed in the free protein. This suggests that the reduction occurs by direct hydride transfer from FMNH− to nitrofurantoin bound in the reverse orientation to that in the crystal structure. We present a model of nitrofurantoin bound to reduced NfsA in a viable hydride transfer orientation. The substrate 1,4-benzoquinone and the product hydroquinone are positioned close to the FMN N5 in the respective crystal structures with NfsA, suitable for reaction, but are mobile within the active site. The structure with a second FMN, bound as a ligand, shows that a mobile loop in the free protein forms a phosphate-binding pocket. NfsA is specific for NADPH and a similar conformational change, forming a phosphate-binding pocket, is likely to also occur with the natural cofactor.
Publisher: Wiley
Date: 17-06-2021
Abstract: Polymer brush surfaces that alter their physical properties in response to chemical stimuli have the capacity to be used as new surface‐based sensing materials. For such surfaces, detecting the polymer conformation is key to their sensing capabilities. Herein, we report on FRET‐integrated ultrathin ( nm) polymer brush surfaces that exhibit stimuli‐dependent FRET with changing brush conformation. Poly( N ‐isopropylacrylamide) polymers were chosen due their exceptional sensitivity to liquid mixture compositions and their ability to be assembled into well‐defined polymer brushes. The brush transitions were used to optically sense changes in liquid mixture compositions with high spatial resolution (tens of micrometers), where the FRET coupling allowed for noninvasive observation of brush transitions around complex interfaces with real‐time sensing of the liquid environment. Our methods have the potential to be leveraged towards greater surface‐based sensing capabilities at intricate interfaces.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Wiley
Date: 25-11-2013
Abstract: In this study, the stereocomplexation between a novel stereospecific cyclic vinyl polymer, that is, cyclic syndiotactic poly(methyl methacrylate) (st-PMMA), with the complementary linear isotactic (it-) PMMA was investigated. Surprising new insight into the effects of the topology (i.e., end groups), size, and tacticity of the assembling components on stereocomplex formation was obtained. Characterization of the stereocomplexes revealed that the self-assembly of cyclic st-PMMAs and linear it-PMMAs resulted in the formation of an unprecedented “polypseudorotaxane-type” supramolecular assembly. This stereocomplex exhibited remarkably different physical properties as compared to the conventional PMMA triple-helix stereocomplex as a result of the restricted topology imposed by the cyclic st-PMMA assembling component.
Publisher: American Chemical Society (ACS)
Date: 13-11-2018
Abstract: Nanostructured materials have potential as platforms for analytical assays and catalytic reactions. Herein, we report the synthesis of electrocatalytically active cobalt phosphate nanostructures (CPNs) using a simple, low-cost, and scalable preparation method. The electrocatalytic properties of CPNs toward the electrooxidation of glucose (Glu) were studied by cyclic voltammetry and chrono erometry in relevant biological electrolytes, such as phosphate-buffered saline (PBS), at physiological pH (7.4). Using CPNs, Glu detection could be achieved over a wide range of biologically relevant concentrations, from 1 to 30 mM Glu in PBS, with a sensitivity of 7.90 nA/mM cm
Publisher: Frontiers Media SA
Date: 16-11-2015
Publisher: Springer Science and Business Media LLC
Date: 10-10-2016
Abstract: The organized assembly of particles into superstructures is typically governed by specific molecular interactions or external directing factors associated with the particle building blocks, both of which are particle-dependent. These superstructures are of interest to a variety of fields because of their distinct mechanical, electronic, magnetic and optical properties. Here, we establish a facile route to a erse range of superstructures based on the polyphenol surface-functionalization of micro- and nanoparticles, nanowires, nanosheets, nanocubes and even cells. This strategy can be used to access a large number of modularly assembled superstructures, including core-satellite, hollow and hierarchically organized supraparticles. Colloidal-probe atomic force microscopy and molecular dynamics simulations provide detailed insights into the role of surface functionalization and how this facilitates superstructure construction. Our work provides a platform for the rapid generation of superstructured assemblies across a wide range of length scales, from nanometres to centimetres.
Publisher: American Chemical Society (ACS)
Date: 17-12-2018
DOI: 10.1021/JACS.8B04436
Publisher: American Chemical Society (ACS)
Date: 27-09-2017
DOI: 10.1021/ACS.LANGMUIR.7B02692
Abstract: Metal-phenolic networks (MPNs) are a versatile class of self-assembled materials that are able to form functional thin films on various substrates with potential applications in areas including drug delivery and catalysis. Different metal ions (e.g., Fe
Publisher: Elsevier BV
Date: 08-2011
DOI: 10.1016/J.BPC.2011.04.002
Abstract: SpvC, a virulence effector injected through type III secretion system by some Salmonella serovars, belongs to the newly discovered enzyme family, phosphothreonine lyase. Previous experimental studies have demonstrated that SpvC irreversibly inactivates mitogen-activated protein kinases by removing the phosphate group from phosphothreonine-containing substrate through a β-elimination mechanism, and results in a β-methyldehydroalanine product. Interestingly, further biochemical investigations also indicated a secondary reaction occurring other than elimination, where a covalently bound complex is formed. Here, we employed molecular dynamics simulations and quantum mechanics calculations to gain insights on the microscopic details of such novel reaction mechanisms. Our theoretical results are consistent with the experimental observations, in which the critical stages of SpvC catalyzed reaction are revealed and the roles of several important binding site residues are reconciled. The deprotonation and precise position of the catalytic base K136 are facilitated by the formation of the fully desolvated active site upon substrate binding. The abstraction of the alpha hydrogen by K136 and the elimination of the phosphate group occur nearly simultaneously, promoted by the proton donation from the catalytic acid H106, and thus strongly supports an E2-like mechanism. K104, which is not directly involved in the enzymatic reaction, stabilizes the transition state and facilitates the reaction to occur. Remarkably, the subsequent deprotonation of K136 happens to be a natural sequel of the primary elimination reaction, restores its nucleophile capacity to attack the double bond containing elimination product, and leads to a covalently bound complex via a Michael-addition mechanism. The reaction mechanism used by phosphothreonine lyases might serve as a method of programmed regulation to fine tune their enzymatic activity.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4SC02971B
Abstract: The structure of the it-/st-poly(methyl methacrylate) (PMMA) triple-helix stereocomplex is composed of a double helix of it-PMMA of 9 units per turn surrounded by a single helix of st-PMMA with an average of 20 units per turn.
Publisher: Portland Press Ltd.
Date: 20-03-2009
DOI: 10.1042/BST0370413
Abstract: NTR (nitroreductase NfsB from Escherichia coli) is a flavoprotein with broad substrate specificity, reducing nitroaromatics and quinones using either NADPH or NADH. One of its substrates is the prodrug CB1954 (5-[aziridin-1-yl]-2,4-dinitrobenzamide), which is converted into a cytotoxic agent so NTR/CB1954 has potential for use in cancer gene therapy. However, wild-type NTR has poor kinetics and binding with CB1954, and the mechanism for the reduction of CB1954 by NTR is poorly understood. Computational methods have been utilized to study potential underlying reaction mechanisms so as to identify the order of electron and proton transfers that make up the initial reduction step and the sources of the protons. We have used Molecular Dynamics to examine the nature of the active site of the wild-type enzyme and the preferred binding mode of the substrate. A combination of these results has allowed us to unequivocally identify the reaction mechanism for the reduction of CB1954 by NTR.
Publisher: CSIRO Publishing
Date: 06-07-2021
DOI: 10.1071/CH21078
Abstract: Deep eutectic solvents (DESs) are tuneable solvents with attractive properties for numerous applications. Their structure–property relationships are still under investigation, especially at the solid–liquid interface. Moreover, the influence of water on interfacial nanostructure must be understood for process optimization. Here, we employ a combination of atomic force microscopy and molecular dynamics simulations to determine the lateral and surface-normal nanostructure of the DES choline chloride:glycerol at the mica interface with different concentrations of water. For the neat DES system, the lateral nanostructure is driven by polar interactions. The surface adsorbed layer forms a distinct rhomboidal symmetry, with a repeat spacing of ~0.9 nm, comprising all DES species. The adsorbed nanostructure remains largely unchanged in 75 mol-% DES compared with pure DES, but at 50 mol-%, the structure is broken and there is a compromise between the native DES and pure water structure. By 25 mol-% DES, the water species dominates the adsorbed liquid layer, leaving very few DES species aggregates at the interface. In contrast, the near-surface surface-normal nanostructure, over a depth of ~3 nm from the surface, remains relatively unchanged down to 25 mol-% DES where the liquid arrangement changed. These results demonstrate not only the significant influence that water has on liquid nanostructure, but also show that there is an asymmetric effect whereby water disrupts the nanostructure to a greater degree closer to the surface. This work provides insight into the complex interactions between DES and water and may enhance their optimization for surface-based applications.
Publisher: AIP Publishing
Date: 20-08-2021
DOI: 10.1063/5.0058605
Abstract: Deep Eutectic Solvents (DESs) are complex solutions that present unique challenges compared to traditional solvents. Unlike most aqueous electrolytes and ionic liquids, DESs have delicate hydrogen bond networks that are responsible for their highly sensitive compositional dependence on the melting point. Prior work has demonstrated a unique nanoscale structure both experimentally and theoretically that brings both challenges and opportunities to their adoption in traditional electrochemical processes. In this study, we use in situ s le-rotated ultra-small angle x-ray scattering to resolve the near-interface solvent structure after electrodepositing Pd nanoparticles onto a glassy carbon electrode in choline chloride:urea and choline chloride:ethylene glycol DESs. Our results indicate that a hierarchical solvent structure can be observed on the meso-scale in the choline chloride:urea and choline chloride:ethylene glycol systems. Importantly, this extended solvent structure increases between −0.3 V and −0.5 V (vs Ag/AgCl) and remains high until −0.9 V (vs Ag/AgCl). Experimentally, the nature of this structure is more pronounced in the ethylene glycol system, as evidenced by both the x-ray scattering and the electrochemical impedance spectroscopy. Molecular dynamics simulations and dipolar orientation analysis reveal that chloride delocalization near the Pd interface and long-range interactions between the choline and each hydrogen bond donor (HBD) are very different and qualitatively consistent with the experimental data. These results show how the long-range solvent–deposit interactions can be tuned by changing the HBD in the DES and the applied potential.
Publisher: American Chemical Society (ACS)
Date: 03-2022
Publisher: American Chemical Society (ACS)
Date: 26-06-2020
Publisher: Springer Science and Business Media LLC
Date: 06-11-2020
DOI: 10.1038/S41524-020-00429-W
Abstract: Organic photovoltaic (OPV) materials are promising candidates for cheap, printable solar cells. However, there are a very large number of potential donors and acceptors, making selection of the best materials difficult. Here, we show that machine-learning approaches can leverage computationally expensive DFT calculations to estimate important OPV materials properties quickly and accurately. We generate quantitative relationships between simple and interpretable chemical signature and one-hot descriptors and OPV power conversion efficiency (PCE), open circuit potential ( V oc ), short circuit density ( J sc ), highest occupied molecular orbital (HOMO) energy, lowest unoccupied molecular orbital (LUMO) energy, and the HOMO–LUMO gap. The most robust and predictive models could predict PCE (computed by DFT) with a standard error of ±0.5 for percentage PCE for both the training and test set. This model is useful for pre-screening potential donor and acceptor materials for OPV applications, accelerating design of these devices for green energy applications.
Publisher: AIP Publishing
Date: 16-11-2017
DOI: 10.1063/1.5005581
Abstract: Complex solvation phenomena, such as specific ion effects, occur in polar liquids. Interpretation of these effects in terms of structure and dispersion forces will lead to a greater understanding of solvation. Herein, using molecular dynamics, we probe the structure of polar liquids through specific dipolar pair correlation functions that contribute to the potential of mean force that is “felt” between thermally rotating dipole moments. It is shown that unique dipolar order exists at separations at least up to 20 Å for all liquids studied. When the structural order is compared with a dipolar dispersion force that arises from local co-operative enhancement of dipole moments, a strong agreement is found. Lifshitz theory of dispersion forces was compared with the structural order, where the theory is validated for all liquids that do not have significant local dipole correlations. For liquids that do have significant local dipole correlations, specifically liquid water, Lifshitz theory underestimates the dispersion force by a factor of 5–10, demonstrating that the force that leads to the increased structure in liquid water is missed by Lifshitz theory of van der Waals forces. We apply similar correlation functions to an ionic aqueous system, where long-range order between water’s dipole moment and a single chloride ion is found to exist at 20 Å of separation, revealing a long-range perturbation of water’s structure by an ion. Furthermore, we found that waters within the 1st, 2nd, and 3rd solvation shells of a chloride ion exhibit significantly enhanced dipolar interactions, particularly with waters at larger distances of separation. Our results provide a link between structures, dispersion forces, and specific ion effects, which may lead to a more robust understanding of solvation.
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2011
End Date: 2011
Funder: National Natural Science Foundation of China
View Funded ActivityStart Date: 2023
End Date: 12-2025
Amount: $439,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2022
End Date: 07-2025
Amount: $422,000.00
Funder: Australian Research Council
View Funded Activity