Phase Transitions of the Potassium Stearate-Water-Polyol Systems

Phase transition phenomena in the water-potassium stearate-polyol (glycerol, propylene glycol, 1, 3-butanediol) systems were studied by differential scanning calorimetry and X-ray diffraction. In the absence of polyols, suitable annealing treatment for the samples was necessary to the gel-to-coagel transition. In the presence of polyols, in the temperature range where the coagel phase is stable state, the gel phase was transformed into the coagel phase without annealing. With increasing polyol content, the transition temperature for the gel-isotropic solution or liquid crystal (Tc) decreased and that for the coagel-gel (Tgel) increased. Therefore, Tc and Tgel coincided with each other at a certain polyol content, and above this content the stable gel phase disappeared and the coagel phase was directly transformed into the isotropic solution. The order of reducing the area of the gel region in the phase diagram was following; 1, 3-butanediol> propylene glycol> glycerol.