In this study a variety of surface modifiers were absorbed onto titania pigment and their interaction examined. / Thesis (PhDAppliedScience)--University of South Australia, 2006.

The wettability of titania is an important factor in numerous industrial and natural processes. It is, as for most oxide surfaces, mainly determined by the density of hydroxyl groups (titanols). / The influence of external stimuli - heat and UV light - on the surface of titania was investigated with a number of surface-sensitive techniques: secondary ion mass spectroscopy, atomic force microscopy, streaming potential and contact angle measurements. Measurements were done in parallel on silica. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005.

The thesis presents a technique for and results of surface force measurements in a 3-phase system. The phases are a solid medium (mica), fluid (water and water-based electrolyte solutions) and gas (an air bubble). Analysis of deformation of the air bubble with respect to mutual position of the bubble and the mica surface, the capillary pressure of the undeformed bubble surface, the capillary pressure, and the disjoining pressure provide data for calculation of the air-liquid surface electrical potential. Furthermore, the information extracted from the deformation analysis made it possible to draw a conclusion regarding the nature of electrical double-layer forces in the system and, to some degree, about the effect of ion properties on the surface charging properties of the air-liquid interface. / Surface forces between an air bubble and a flat mica surface immersed in aqueous electrolyte solutions have been investigated using a modified surface force apparatus. This method allows forces to be detected in two regimes: at long range where the bubble is distorted slightly by the surface forces, and at short range where the force is manifest as disjoining pressure in a thin wetting film separating the bubble from the solid. The force was calculated from the equilibrium (or quasi-equilibrium) shape of the bubble surface. The experiments clearly show that long-range double-layer repulsion acts between mica and an air bubble in water and electrolyte solutions of different concentration. Double-layer repulsion indicates that the air bubble surface is negatively charged. However, there is clear evidence that charge regulation occurs at the air-water interface to maintain a constant surface potential, and as a result of this, the charge at this interface changes from negative to positive as the bubble approaches the negatively charged mica surface. Because of the attraction that arises due to the charge reversal, excessive force is required to separate the bubble from the mica, though the mica remains completely wetted by the aqueous phase. / The air-liquid surface potential has been evaluated from fitting a theoretically calculated shape to experimental measurements of bubble shape and film thickness, where the theoretical bubble shape was obtained from the numerical solution of the augmented Young-Laplace equation. Potential on the air bubble surface mainly depends on the concentration of electrolyte but is insensitive to the type of cation or anion within the low range of concentration investigated here. / The more important issue for such concentrations appears to be the electrostatic interaction between ions in solution and the air bubble interface. Therefore at the concentrations investigated, the potential on the gas-liquid interface arises due to the non-specific adsorption of ions to oriented water dipoles at the interface. / Thesis ([PhDApSc(MineralsandMaterials)])--University of South Australia, 2005.

The aim of the research presented in this thesis was to increase the understanding of the interaction between polymeric dispersants and titania pigment particles. In particular, the effects of dispersants of varied functionalities on the pigment dispersion behaviour in both aqueous suspension and dry paint film were investigated. / Thesis (PhDEng(MineralsandMaterials))--University of South Australia, 2004.

Hydrophobic colloidal suspensions are common in nature and industry. DLVO theory has been used to model the interactions between colloidal particles for decades, however the origin of long-ranged attractive forces observed between hydrophobic colloids remains the subject of much debate. In an effort to understand these forces and improve the prediction of colloidal stability, the colloidal stability of synthetic silica and titania was studied at various concentrations of dissolved gas, KCl electrolyte and pH. / Thesis (PhD)--University of South Australia, 2003

Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2001.

Thesis (PhD) -- University of South Australia, 1992

Thesis (PhD)--University of South Australia, 1999

A combination of surface analytical techniques, colloid probe Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS) was used to optimise the grafting density of covalently attached 5, 20 and 40 kDa methoxy-terminated PEO layers (under marginal solvation (cloud point) conditions for the PEO molecules). The combination of these techniques allowed us to relate the PEO layer density and molecular conformations to the range, magnitude and types of forces generated by coatings of various grafting densities. The key optimisation parameter was the grafting time with the concentration of PEO in solution having a weaker effect. Oxidation of the substrate occurred, but did not significantly limit the surface density of the functional groups used to chemically attach the PEO molecules. Interactions between the substrate and silica were electrostatic in origin and did not contribute to the interaction between silica and the PEO surfaces due to salt screening effects Surfaces with dense, highly stretched PEO layers (brushes) generated purely repulsive forces at all separation distances, arising from compression by the silica spherical probe used. The force profiles for lower density surfaces comprised long-ranged attractive and short-ranged repulsive forces. The attractive forces were most likely due to attractive bridging interactions between the PEO chains and the SiO2 surface. For low grafting densities, i.e. inter-chain grafting distances, s &gt ??RF, the PEO layers were not strongly stretched and free to adsorb onto the opposing silica surface. XPS analysis demonstrated that HSA and Fibrinogen adsorbed onto low density 20 kDa PEO coatings (s &gt ??RF), most likely via diffusion through the PEO layer. No protein adsorption was found (detection limit &gt 10 ng/cm2) on high density, ???strongly stretched brush??? coatings (s &lt ?? RF). Analysis of data from the more sensitive Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) techniques indicated that low amounts of adsorbed HSA, lactoferrin, lysozyme, and IgG were present on high density 20 and 40 kDa surfaces; the most likely explanation being attractive interactions between the proteins and the PEO layers during the protein adsorption experiments. ToF-SIMS data obtained for the strongly stretched (s &lt ?? RF) 5 kDa PEO surfaces suggested that no protein was adsorbed, in line with the XPS data for the same surfaces.

Bibliography: leaves 209-254. / viii, 254, [39] leaves, [17] leaves of plates : ill. 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Attempts to construct an evolutionary overview of the regulation of surfactant secretion among the vertebrates. A detailed whole animal and in vitro study of the factors that control surfactant secretion and function in the central Australian agamid lizard Pogona vitticeps was undertaken. Type II pneumocytes were also isolated and cultured from Australian lungfish, North American bullfrogs and fat-tailed dunnarts. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physiology, 1999