M. R. Davidson

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A new, atomic force microscopy (AFM) based experimental setup for the continuous acquisition of friction force data as a function of humidity has been developed. The current model of interactions between wet contacts under the influence of capillary effects, has been amended to include a vertical component due to the disjoining pressure and takes into(More)
The hydration-dehydration process of an adsorbed human serum albumin film has been studied using atomic force microscopy (AFM) and a quartz crystal microbalance (QCM). All measurements were performed with identically prepared protein films deposited on highly hydrophilic substrates. Both techniques are shown to be suitable for following in situ the kinetics(More)
Ultra-violet Ozone (UVO) modified polystyrene (PS) surfaces were analyzed by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle (CA), optical microscopy (OM) and cell culture experiments. UV/Ozone treatment up to 900 s was used to increase the surface oxygen concentration of PS surfaces from 0% to approximately 35%(More)
Ultra-high-molecular-weight polyethylene (UHMWPE) has a long history of use in medical devices, primarily for articulating surfaces due to its inherent low surface energy which limits tissue integration. To widen the applications of UHMWPE, the surface energy can be increased. The increase in surface energy would improve the adsorption of proteins and(More)
In this paper we investigate the importance of electrostatic double layer forces on the adsorption of human serum albumin by UV-ozone modified polystyrene. Electrostatic forces were measured between oxidized polystyrene surfaces and gold-coated atomic force microscope (AFM) probes in phosphate buffered saline (PBS) solutions. The variation in surface(More)
The plasma polymerization of acetone has been used to modify polystyrene substrates for the controlled growth of human fibroblast cells. The surface modified polystyrene was studied by X-ray photoelectron spectroscopy, water contact angle and atomic force microscopy. This showed the surface oxygen levels and wettability to increase rapidly with exposure to(More)
UV/ozone oxidation was combined with a photomasking technique to produce adjacent regions of different chemistry on polystyrene (PS) surfaces. The surface chemistry and topography were studied using AFM, XPS and contact angle measurements. The physicochemical patterns were visualised by the condensation of water vapour upon the surfaces and by the(More)
Plasma polymerisation is of great interest for modifying the surface properties of biomedical devices in order to control, for example, protein adsorption and cell attachment. In this paper we present results for plasma-polymerised acetonitrile deposited onto silicon or polystyrene substrates. The chemistry of films deposited under a range of experimental(More)
The electroviscous flow at low Reynolds number through a two-dimensional slit contraction with electric double-layer overlap is investigated numerically for cases where the permittivity of the wall material is significant in comparison with the permittivity of the liquid. The liquid-solid interface is assumed to have uniform surface-charge density. It is(More)