We have investigated the microstructures of the solid residue left behind after the evaporation of solid-stabilised emulsions. The correlation between the microstructure and the properties and preparation conditions of the emulsions will be thoroughly discussed. The type of microstructure is related to the conditions (oil type, oil content, particle type, particle concentration and emulsion type) of the initial emulsion. Solid residues left after evaporation of oil-in-water emulsions containing volatile oils (relative to water) show a “knobbly” microstructure. When oils with similar or lower vapour pressure to that of water were used, “sponge-like” structures were obtained. For emulsions containing volatile oils, the mean drop diameter is similar to the mean pore diameter, whereas when oils with low vapour pressure are used, the pores are much smaller. Finally, this paper will illustrate that stable toluene-in-water emulsions leave porous microstructures, whereas water-in-toluene emulsions and emulsions close to the phase inversion show sheet-like or “knobbly” structure.
1.Institute for Polymer Materials POLYMAT and Grupo de Ingeniería Química, Departamento de Química Aplicada, Facultad de Ciencias QuímicasThe University of the Basque CountryDonostia-San SebastianSpain
2.Surfactant & Colloid Group, Department of ChemistryUniversity of HullHullUK