Salt induced polystyrene latex flocs investigated by neutron scattering.

Studies with a model system consisting of polystyrene latex particles showed that the protein from seeds of Moringa trees adsorbs to the surface and causes flocculation as unusually dense aggregates. In this study, electrolytes sodium chloride (NaCl), ferric chloride (FeCl) and aluminium sulfate (Al(SO)) have been used to aggregate model polystyrene particles. The study augments previous work using neutron scattering on the flocculation of polystyrene latex with protein from seeds of Moringa trees that had indicated higher floc dimension, d, values as the concentration of particles increased.

Interactions between quaternary ammonium surfactants and polyethylenimine at high pH in film forming systems.

Hypothesis: Film formation and film structure in films formed on solutions of cationic surfactants with polyethylenimine is influenced by the surfactant structure, including both the tail length and the nature of the headgroup, which alter the micelle properties.

Experiments: A series of cationic surfactants were synthesized and conductivity measurements were used to compare the critical micelle concentrations for these surfactants and their behaviour with and without polyethylenimine at high pH. Small angle neutron scattering measurements were used to characterise the size and shape of the micelles in the presence and absence of the polymer.

CO₂-responsive microemulsions based on reactive ionic liquids.

We demonstrate that the nanodomains within a ternary system consisting of oil, surfactant, and a new reactive ionic liquid can be tuned reversibly upon exposure to and removal of CO2 under mild conditions of temperature and pressure. The equilibrium microstructures of these domains have been characterized by small-angle neutron scattering and demonstrate that control over emulsion morphology (and therefore physicochemical properties such as viscosity) and the breaking of emulsions can be achieved without the need for irreversible changes in system composition or significant energy input.

Spatially Resolved Concentration and Segmental Flow Alignment in a Shear-Banding Solution of Polymer-Like Micelles.

We measure the spatially resolved microstructure and concentration in the plane of flow for a viscoelastic solution of polymer-like micelles comprised of mass fraction 6.0% (volume fraction 6.6%) solution of 2:1 molar ratio cetylpyridinium chloride/sodium salicylate in 0.

Self-assembled films formed at the air-water interface from CTAB/SDS mixtures with water-soluble polymers.

We have investigated the spontaneous self-assembly of solid, mesostructured films that form at the air-solution interface on solutions containing a neutral water-soluble polymer and catanionic surfactant mixtures of hexadecyl-trimethylammonium bromide (CTAB) and sodium dodecylsulphate (SDS). The formation processes and structures were probed using neutron reflectivity, X-ray reflectivity, off-specular time-resolved scattering, and grazing incidence diffraction. The mesostructures of films prepared with polyethylene oxide, polyethylenimine, and polyacrylamide at various cationic/anionic surfactant molar ratios are compared.