Structural study of aerosol-OT-stabilised microemulsions of glycerol dispersed in n-heptane

Abstract

Thermodynamically stable Aerosol-OT-stabilised dispersions of glycerol in n-heptane (microemulsions) have been studied using dynamic light scattering and viscometry. Up to five moles of glycerol can be dispersed per mole of aerosol-OT in n-heptane. The resulting solutions consist of discrete spherical droplets of glycerol stabilised by the surfactant. Droplet size is independent of temperature and depends primarily on the mole ratio (R) of glycerol to AOT according to hydrodynamic radius/nm = 1.7(±0.2)+0.88(±0.15)R. The apparent interfacial area occupied per AOT molecule is ca. 20% less in the glycerol dispersion than in the corresponding water dispersion. Attractive interactions between the droplets increase as the microemulsion phase stability limit is approached.