Structures and Mechanisms of Phase Transitions in Surfactant Mixtures: Systems Which Induce the Ribbon Phase

Abstract

Abstract Phase transitions in lyotropic liquid crystal systems made from potassium palmitate/potassium laurate/water (KP/KL/H2O) and potassium palmitate/benzoyl alcohol/water (KP/BZA/H2O) were characterized by time resolved x-ray diffraction done at the SERC Daresbury (U.K.) Synchrotron Laboratory. Hysteretic phase behavior was observed for some of the KP/KL/H2O mixtures but not for any of the KP/BZA/H2O mixtures studied. In addition, the transition between the rectangular and ribbon phases in these systems is described using x-ray diffraction. General trends related to the observation of phase transitions in these systems are discussed. The ribbon phase appears to be more stable in the KP/BZA/H2O system since it retains its structure after the coexisting lamellar phase has transformed into a liquid crystalline bilayer for a larger temperature range than for KP/KL/H2O.