Paul D I Fletcher

Learn More
Water films stabilised by hydrophobic particles are found to spread rapidly up the inner walls of a glass vessel containing water and hydrophobic particles when it is shaken; shaking produces unstable particle-stabilised foam bubbles whose coalescence with the air/water interface drives film growth up the inner walls of the container.
Aqueous solutions containing a mixture of polyethylene glycol (PEG) and dextran homopolymers form an aqueous two-phase system which can be emulsified to give a water-in-water emulsion. We show how these emulsions can be stabilized using triblock polymers containing poly[poly(ethylene glycol) methyl ether methacrylate] (PEGMA), poly (n-butyl methacrylate)(More)
Results are reported for ellipsometric measurements of hydrophobized monodisperse silica particles, with a diameter of about 25 nm, spread at the toluene-water interface. Theoretical values for the ellipsometric parameters are derived by treating the particles as a core-shell model and performing integrations of the refractive index profile through the(More)
Phase inversion of fumed silica particle-stabilised emulsions of water and perfume oil can be effected in three ways. The transitional inversion from water-in-oil (w/o) to oil-in-water (o/w) occurs upon increasing the particle hydrophilicity for 9 oils of different polarity and structure. Results are compared for systems in which particles are pre-dispersed(More)
Addition of a cationic surfactant to a solution of DNA causes the formation of compacted DNA-cationic surfactant complexes which precipitate from aqueous solution. It has been shown previously that addition of anionic surfactant will re-dissolve and de-compact the DNA-cationic surfactant complexes and we find that addition of non-ionic surfactants of the(More)
We derive a unified model that accounts for the variation in extent and rate of membrane permeation by a permeating species with the type of donor compartment formulation (aqueous and oil solutions, particle dispersions, and oil-in-water and water-in-oil emulsions stabilized by particles) initially containing the permeant. The model is also applicable to(More)
When beta-ionone-in-water emulsions are mixed with squalane-in-water emulsions, the slightly water-soluble, mobile beta-ionone undergoes mass transfer to the drops of highly water-insoluble, immobile oil squalane. We have investigated this compositional ripening process for emulsions stabilised either by particles or by surfactant molecules. For(More)