The effects of polyhydric alcohols on the viscosity, electric conductivity and phase transition temperature of a octadecyl-trimethylammonium chloride (OTAC)/1-hexadecanol (C16OH)/water system were studied. Propylene glycol had significant effect on the physical properties of this ternary system, while glycerol did not. Following the addition of propylene glycol to the system having a low molar ratio (1.0) of C16OH to OTAC, viscosity decreased considerably accompanied by the disappearance of the rapid rise in electric conductivity at about 43°C. An endothermic peak at about 43°C also disappeared. Association of OTAC, C16OH and water would thus appear to be altered as a result of adding propylene glycol, this being likely due to the amphiphilic feature of the system.
