Preparation and Flow Behaviour of Oil-In-Water Emulsions Stabilised by Hydrophilic Silica Particles

Emulsions are a common form of material and are encountered in products including foods, cosmetics, and pharmaceuticals. Appropriate formulation and processing ensures stability and quality. The research reported is concerned with the use of nano‐particles for interfacial stabilisation of oil‐in‐water (o/w) emulsions. This is a route far less often chosen by formulation engineers than interfacial stabilisation based on small molecular surfactants. Known concepts of stabilising simple o/w emulsions with hydrophilic silica particles were applied. The emulsion components were carefully selected in view of their application relevance in consumer goods such as foods and creams. Emulsions stable against coalescence were formulated based on discrete 230 nm silica particles and corn oil. The viscosity behaviour of the emulsions was characterised after suppressing creaming through dissolution of a thickening agent in the continuous emulsion phase. The emulsions were shear‐thinning and viscosity levels were reduced after removal of free particles. Particle stabilisation of o/w interfaces alters the product characteristics of emulsion‐based products, giving formulation engineers novel ways to adjust product rheologies. Particle stabilisation of o/w interfaces alters the product characteristics of emulsion‐based products, giving formulation engineers novel ways to adjust product rheologies. The viscosity behaviour of particle‐stabilised emulsions is investigated, paying particular attention to the effect of free nanoparticles – not adsorbed at the o/w interface – on the viscosity behaviour.