Page 1. 9130 J. Am. Chem. SOC. 1992, 11 4, 9 130-9 136 that was measured at I/IsAT = 1 and are plotted as a function of Z/ZsAT in Figure 10. Figure 10 shows that the maximum reflectivity, hence signal-to-noise ratio, is obtained at... more
Page 1. 9130 J. Am. Chem. SOC. 1992, 11 4, 9 130-9 136 that was measured at I/IsAT = 1 and are plotted as a function of Z/ZsAT in Figure 10. Figure 10 shows that the maximum reflectivity, hence signal-to-noise ratio, is obtained at intensities approximately equal to ISAT. ...
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The microstructure of a series of oil-in-water emulsions, formed in the toluene/triton X-100/water system, was investigated as a function of energy input during the formulation process. Emulsion microstructure could be manipulated for a... more
The microstructure of a series of oil-in-water emulsions, formed in the toluene/triton X-100/water system, was investigated as a function of energy input during the formulation process. Emulsion microstructure could be manipulated for a single emulsion composition by changing only the amount of energy supplied during emulsification. Four different emulsion microstructures are realisable in this system: two distinct discrete oil droplet
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The self-diffusion coefficients of water and casein aggregates in aqueous Na-caseinate dispersions were measured using a pulsed gradient stimulated echo nuclear magnetic resonance technique (PGSTE-NMR). The results for water... more
The self-diffusion coefficients of water and casein aggregates in aqueous Na-caseinate dispersions were measured using a pulsed gradient stimulated echo nuclear magnetic resonance technique (PGSTE-NMR). The results for water self-diffusion are discussed in terms of the cell model. The influence of Na-caseinate concentration on water self-diffusion can be explained by obstruction and tortuosity effects arising due to the presence of
Research Interests: Engineering, Water, Nuclear Magnetic Resonance, Rheology, DISTRIBUTION, and 16 moreDispersion, Models, Gradient, Diffusion, Physical sciences, Aggregate, Difusion, CHEMICAL SCIENCES, Rheological properties, Diffusion Coefficient, Fine Structure Constant, Size Distribution, Microstructures, Distribution, Self-diffusion, and Shear
The ability to determine the calcium carbonate polymorphic ratio of calcite, aragonite and vaterite in a mixture is important for a variety of applications, particularly the fields of biomineralisation and crystal engineering. Raman... more
The ability to determine the calcium carbonate polymorphic ratio of calcite, aragonite and vaterite in a mixture is important for a variety of applications, particularly the fields of biomineralisation and crystal engineering. Raman spectroscopy and powder X-ray diffraction were used to quantitatively determine the polymorphic composition of both binary and tertiary mixtures of calcium carbonate. It was found that the quantitative detection limits of powder X-ray diffraction were superior to both Raman and infrared spectroscopy.
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The correlation of molecular diffusion coefficients obtained via a novel two-dimensional pulsed gradient spin-echo (PGSE) NMR method has been shown to reveal detailed structural information on the mesophases of lyotropic liquid crystals.... more
The correlation of molecular diffusion coefficients obtained via a novel two-dimensional pulsed gradient spin-echo (PGSE) NMR method has been shown to reveal detailed structural information on the mesophases of lyotropic liquid crystals. A four-component system containing both nonionic (pentaethylene glycol monododecyl ether) and ionic (sodium dodecyl sulfate) surfactants, water, and decane was prepared and left to equilibrate. In the temperature region around 309 K, a lamellar mesophase forms. A two-dimensional Laplace inverse transformation was performed on the (gammadeltag)2(delta - delta/3) domain data to separate any multiexponential behavior that resulted from local anisotropy. The results of the double PGSE experiment with contiguous gradient pulse pairs, applied both collinearly and orthogonally, clearly show the presence of local anisotropic self-diffusion of the water molecules and suggest a preferred orientation of the lamellae. Information about defects/domain size was obtained by the insertion of a mixing time (t(m)') between the successive gradient pulse pairs. This work highlights the value of this new NMR correlation method in the study of surfactant systems.
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Research Interests: Engineering, Chemistry, Water, Structure, Alcohol, and 20 morePhysical sciences, Nucleation, Mechanism, Hydrogen Bond, Membrane, CHEMICAL SCIENCES, Hydrogen Bonding, SOAP, Equilibrium, Surface Properties, Calcium Carbonate, Potential Energy Surface, Surface Pressure, Calcium Chloride, Monolayer, Langmuir Monolayer, Intermolecular Interaction, Sodium Bicarbonate, Static Electricity, and soaps
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Chitosan hydrogels are of considerable interest in synthetic biomimetic mineralisation strategies due to their favourable characteristics such as the presentation of a large surface area for crystal nucleation within a structured yet... more
Chitosan hydrogels are of considerable interest in synthetic biomimetic mineralisation strategies due to their favourable characteristics such as the presentation of a large surface area for crystal nucleation within a structured yet responsive scaffold. Chitosan hydrogels were prepared and subsequently calcium carbonate mineralisation was initiated using a method which combines alternate soaking of the films with precursor solutions followed by treatment with Kitano solution. This combined approach allows for increased extent of mineralisation, inducement of mineralisation uniformly throughout the hydrogel rather than only at the peripheral surface and ready scalability and shape manipulation. The base synthetic system is readily modified through the introduction of additives that manipulate the nucleation and growth of the calcium carbonate. Addition of poly(acrylic acid) inhibits nucleation and induces tangential crystal growth along the internal and external interfaces of the hydrogel. The resulting composite is comprised of stacked overlapping plates of calcium carbonate intercalated with carbohydrate. The method is applicable in combination with a variety of hydrogels including macroporous chitosan, chitosan-alginate bilayers and pure alginate hydrogels. The composite materials were analysed by SEM, XRD, microRaman spectroscopy and mechanical strength testing.
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Surface interaction forces for colloidal alumina have been measured by atomic force microscopy (AFM) in solutions containing sulfate salts of +3 metal ions in an attempt to better understand the role of Al3+- and Fe3+-based coagulants... more
Surface interaction forces for colloidal alumina have been measured by atomic force microscopy (AFM) in solutions containing sulfate salts of +3 metal ions in an attempt to better understand the role of Al3+- and Fe3+-based coagulants commonly used in water and waste treatment. The results have been compared to classical coagulation studies using a jar test apparatus. The relative order