L ₃ phases: Their structure and dynamic properties

Abstract

The phase behavior of ternary systems made from alkyldimethylaminoxide as zwitterionic surfactant, long-chain alcohols as cosurfactant, and water was investigated with respect to the occurrence of a L ₃ phase. In almost all of the systems, it was possible to verify the existence of such a phase in the vicinity of a corresponding lamellar phase. In addtion, in the case of C₁₄DMAO with heptanol and its higher homologues, it was possible, not only to obtain a conventional L ₃ phase, but also a principally similar phase at lower cosurfactant concentrations (L′₃ phase) that differs from the first one mainly by its much higher viscosity and by a much more pronounced streaming birefringence. All the L ₃ phases investigated were characterized by means of electrical birefringence experiments, dynamic light-scattering, and viscosity measurements.