ORCID Profile
0000-0003-3392-136X
Current Organisation
University of South Australia
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Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5SM02546J
Abstract: We investigated the boundary conditions for flow of a Newtonian liquid over soft interfaces by measuring hydrodynamic drainage forces with colloid probe atomic force microscopy in a viscous liquid. The investigated soft surfaces are end-grafted brushes of thiolated poly(ethylene glycol) (PEG), of molecular weight 1k and 30k, grafted-to gold. The conditions for brush preparation were optimized as to meet the stringent conditions required for surface force measurements, namely reproducible and uniform surface composition and roughness. The fit of a slip model to the experimental data returned a slip length of 16 nm on the PEG 1k brush and 25 nm on the PEG30k brush. The slip length can be interpreted as a penetration length, which accounts for flow within the top half of the brush for the PEG30k case, and within the brush and surface roughness for the PEG1k case. These findings confirm earlier simulation studies by our group on the flow of liquids within polymer brushes.
Publisher: American Chemical Society (ACS)
Date: 09-07-2010
DOI: 10.1021/JP910965P
Abstract: Static and dynamic interaction forces between two thermosensitive polymeric nanoparticle monolayers grafted onto mica surfaces and immersed in water were studied using a surface forces apparatus. The polymeric nanoparticles (NPs) were made of N,N-diethylacrylamide and had a hydrodynamic diameter of ca. 780 nm at 20 degrees C in aqueous suspension. They were irreversibly grafted onto chemically modified mica surfaces at a constant surface coverage of 2.6 NPs/mum(2). The measured normal forces between two opposing NP monolayers were found to be strongly dependent on the temperature. At temperatures lower than the lower critical solution temperature (LCST), the grafted NPs were swollen, and the normal interaction forces between the two NP monolayers were repulsive. Above the LCST, the NPs collapsed, and attractive forces between the NP layers were measured. The swollen NPs were found to exhibit very low friction forces compared to the collapsed ones. The effect of the sliding velocity on the shear stress was investigated, and the results are in agreement with the so-called adhesive friction model developed for rubber friction. Our results suggest that the water content in the contact area and the interdiffusion of polymer chains are important parameters in determining the friction between polymer-bearing surfaces.
Publisher: Elsevier BV
Date: 05-2016
Publisher: American Chemical Society (ACS)
Date: 15-03-2017
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.CIS.2014.02.015
Abstract: Advancements in the fabrication of microfluidic and nanofluidic devices and the study of liquids in confined geometries rely on understanding the boundary conditions for the flow of liquids at solid surfaces. Over the past ten years, a large number of research groups have turned to investigating flow boundary conditions, and the occurrence of interfacial slip has become increasingly well-accepted and understood. While the dependence of slip on surface wettability is fairly well understood, the effect of other surface modifications that affect surface roughness, structure and compliance, on interfacial slip is still under intense investigation. In this paper we review investigations published in the past ten years on boundary conditions for flow on complex surfaces, by which we mean rough and structured surfaces, surfaces decorated with chemical patterns, grafted with polymer layers, with adsorbed nanobubbles, and superhydrophobic surfaces. The review is ided in two interconnected parts, the first dedicated to physical experiments and the second to computational experiments on interfacial slip of simple (Newtonian) liquids on these complex surfaces. Our work is intended as an entry-level review for researchers moving into the field of interfacial slip, and as an indication of outstanding problems that need to be addressed for the field to reach full maturity.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CP03438A
Abstract: Plasma synthesised Si QDs are deposited in liquids to decouple confinement and passivation effects on their optical properties.
Publisher: Wiley
Date: 20-07-2012
Publisher: American Chemical Society (ACS)
Date: 09-09-2009
DOI: 10.1021/LA9026915
Abstract: In this communication, we report an inexpensive and simple-to-implement method using self-assembly properties of surfactants onto solid substrates for patterning square centimeter surfaces with a high density of catalyst metal nanoparticles with narrow size distributions. This method, which uses patterns of hemimicelles of partially fluorinated alkanes as masks and over metal evaporation, leads to typical particle sizes and spacings of 2 and 25 nm, respectively, arranged in a hexagonal network with a density of about 10(11) particles/cm2. Using gold as the metal, we show the ability of such material to catalyze the oxidation reaction of carbon monoxide into carbon dioxide at low temperature.
Publisher: Wiley
Date: 28-03-2017
Publisher: Springer Science and Business Media LLC
Date: 12-04-2013
Publisher: American Chemical Society (ACS)
Date: 10-05-2019
Publisher: Springer Science and Business Media LLC
Date: 25-09-2017
DOI: 10.1007/S00216-017-0639-5
Abstract: Amylose, one of the components of starch, is a glucose polymer consisting largely of long, linear chains with a few long-chain branch points. The chain-length (molecular weight) distribution (CLD) of the component chains of amylose can provide information on amylose biosynthesis-structure-property relations, as has been done previously by fitting amylopectin CLDs to a model with physically meaningful parameters. Due to the presence of long chains, the CLD of amylose can currently best be obtained by size-exclusion chromatography, a technique that suffers from band-broadening effects which alter the observed distribution. The features of the multiple regions present in amylose chain-length distributions are also difficult to resolve, an issue that combines with band broadening to compound the difficulty of analysis and subsequent parameterization of the structural characteristics of amylose. A new method is presented to fit these distributions with biologically meaningful parameters in a way that accounts for band broadening. This is achieved by assuming that band broadening takes the form of a simple Gaussian over a relatively small region and that chain stoppage is a random process independent of the length of the substrate chain over the same region these assumptions are relatively weak and expected to be frequently applicable. The method provides inbuilt consistency tests for its applicability to a given data set and, in cases where it is applicable, allows for the first nonempirical parameterization of amylose biosynthesis-structure-property relations from CLDs by using parameters directly linked to the activities of the enzymes responsible for chain growth and chain stoppage. Graphical abstract Model calculation illustrating the method described and showing the ision between the three characteristic regions of a typical amylose chain-length distribution.
Publisher: Wiley
Date: 20-05-2008
DOI: 10.1002/POLB.21468
Publisher: Wiley
Date: 08-12-2016
Publisher: Springer Science and Business Media LLC
Date: 31-03-2017
DOI: 10.1038/BCJ.2017.27
Abstract: Myeloma is heterogeneous at the molecular level with subgroups of patients characterised by features of epigenetic dysregulation. Outcomes for myeloma patients have improved over the past few decades except for molecularly defined high-risk patients who continue to do badly. Novel therapeutic approaches are, therefore, required. A growing number of epigenetic inhibitors are now available including EZH2 inhibitors that are in early-stage clinical trials for treatment of haematological and other cancers with EZH2 mutations or in which overexpression has been correlated with poor outcomes. For the first time, we have identified and validated a robust and independent deleterious effect of high EZH2 expression on outcomes in myeloma patients. Using two chemically distinct small-molecule inhibitors, we demonstrate a reduction in myeloma cell proliferation with EZH2 inhibition, which leads to cell cycle arrest followed by apoptosis. This is mediated via upregulation of cyclin-dependent kinase inhibitors associated with removal of the inhibitory H3K27me3 mark at their gene loci. Our results suggest that EZH2 inhibition may be a potential therapeutic strategy for the treatment of myeloma and should be investigated in clinical studies.
Publisher: American Chemical Society (ACS)
Date: 15-03-2017
Publisher: Elsevier BV
Date: 03-2017
Publisher: American Chemical Society (ACS)
Date: 04-01-2016
Abstract: Prompted by the rapidly developing field of wearable electronics, research into biocompatible substrates and coatings is intensifying. Acrylate-based hydrogel polymers have gained widespread use as biocompatible articles in applications such as contact and intraocular lenses. Surface treatments and/or coatings present one strategy to further enhance the performance of these hydrogels or even realize novel functionality. In this study, the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is deposited from the vapor phase onto hydrated hydrogel substrates and blended with biocompatibilizing coconstituents incorporating polyethylene glycol (PEG) and polydimethyl siloxane (PDMS) moieties. Plasma pretreatment of the dehydrated hydrogel substrate modifies its surface topography and chemical composition to facilitate the attachment of conductive PEDOT-based surface layers. Manipulating the vapor phase polymerization process and constituent composition, the PEDOT-based coating is engineered to be both hydrophilic (i.e. to promote biocompatibility) and highly conductive. The fabrication of this conductively coated hydrogel has implications for the future of wearable electronic devices.
Publisher: American Chemical Society (ACS)
Date: 11-12-2019
Publisher: Wiley
Date: 28-11-2017
Publisher: Elsevier BV
Date: 04-2016
Publisher: Elsevier BV
Date: 04-2019
Publisher: American Chemical Society (ACS)
Date: 20-04-2009
DOI: 10.1021/LA803434B
Abstract: Analysis of the adhesive contact between solids makes use of contact mechanics, surface physics, and fracture mechanics. The elastic adhesive contacts have been intensively studied, and now, interest still remains about how the viscoelasticity of the solids may be taken into account for the calculation of the work of adhesion, the major difficulty being to separate the surface and bulk energy dissipations. This paper describes a new and original experimental device for "dynamic JKR" tests, which allows us to study dynamic adhesive contacts under a cyclic normal load. PDMS contacts on PDMS were studied at different frequencies and temperatures, and it was possible using the JKR model to determine the hysteretic value of the work of adhesion. The results obtained follow the same evolution as the loss factor of the material.
No related grants have been discovered for Eric Charrault.