Phase behaviour of binary and ternary non-aqueous aerosol OT systems

Abstract

Binary and ternary phase diagrams have been determined for systems containing sodium di-2-ethylhexylsulfosuccinate (Aerosol OT); a polar solvent, formamide, methylformamide, dimethylformamide or ethanediol; with and without hydrocarbon, toluene or dodecane. In formamide, Aerosol OT forms a lamellar, a viscous isotropic (cubic) and a reverse hexagonal liquid crystalline phase. The swelling of the lamellar phase, as well as its temperature stability, is considerably reduced compared to the corresponding aqueous system. In the other solvents, only the reverse hexagonal phase forms. The ternary systems with toluene are generally dominated by an extensive solution region, i.e. a non-aqueous microemulsion, while with dodecane, the solution phase has a considerably reduced extension.