Structure of microparticles and nanoparticles in solid-stabilized emulsions

Emulsions of oil and water stabilized by adsorbed solid particles are known as solid-stabilized emulsions (often referred to as Pickering emulsions). A study on the self-assembly of colloidal-sized polystyrene particles and alkanethiol-capped silver nanopaticles in Pickering emulsions was carried out. The polystyrene microparticles aggregated and formed a monolayer with small patches with local hexagonal order at low interfacial concentrations. Polystyrene particles with different sizes and different wettability could simultaneously segregate to the emulsion interface and form mixtures on it. In contrast to microparticles that form monolayers, the dodecanethiol-capped silver nanoparticles of 1-5 nm formed randomly distributed multilayers at the liquid/liquid interface, with an interparticle distance varying from close contact to ∼ 25 nm. This is an abstract of a paper presented at the AIChE Annual Meeting and Fall Showcase (Cincinnati, OH 10/30/2005-11/4/2005).