Formation of two lamellar phases in the dilute region of a quasiternary surfactant system

In the dilute region (between 65 and 95% solvent by weight) of the quasiternary system cetylpyridinium chloride/hexanol/1 wt % NaCl solution two distinct lamellar phases have been observed to exist. The two phases differ in several physical aspects including their inherent defect nature, turbidity, density, viscosity, and characteristic interlamellar distance. The existence of a region of coexistence between the two lamellar phases is masked by its extreme sensitivity to temperature changes, the formation of a mesoemulsion, and the often extremely long equilibration times. A neutral polymer, polyacrylamide, was added as a component of the solvent to the system and was taken up more readily by the more dilute lamellar phase.