NONIDEAL BEHAVIOR OF MIXED MICELLES IN IONIC END NONIONIC SURFACTANT SYSTEMS

The behaviour at mixing of some cationic surfactants, such as alkylpyr idinium halides with polyethoxylated nonionic surfactant was investiga ted. The surface tension of mixed surfactant systems in aqueous soluti on as a function of the mole fraction of the ionic surfactant in solut ion was determined at various temperatures. The critical micelle conce ntration of the mixed system and the maximum surface excess at the air - solution interface were calculated from the surface tension isother ms. The mole fraction of the ionic surfactant in the mixed micelle and the interaction parameter were obtained from the experimental surface tension data, using the regular solution theory.