PREDICTION OF INTERFACIAL PROPERTIES IN MICROEMULSIONS - THE LATTICE FLUID SELF-CONSISTENT-FIELD THEORY

A lattice fluid self-consistent field theory is used to calculate both the composition and fundamental thermodynamic properties, i.e., the interfacial tension (gamma) and bending moment (c), of spherical interfaces between oil and water. The variation in density throughout the interface is treated by the inclusion of holes in the lattice. This molecular theory is inserted into new classical thermodynamic expressions for gamma and c which take into account the fact that the surfactant tails are anchored to an interface. The detailed description of the composition throughout the interface provides a means to understand the effect of density and radius on the bending moment. The natural curvature and interdroplet interactions are calculated for water-in-propane microemulsions formed with the surfactant Aerosol-OT and compared with experiment.