Study of Mixed Micelles and Interaction Parameters

Surface tension (ST) measurements were carried out on various binary mixtures of the “normal” surfactants, such as nonionic surfactant, hexaethylene glycol mono-n-dodecyl ether(C12EO6, and cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), and polymeric copolymer, Pluronic F127, F127(PPO)-g-PVP, and F127(PEO)-g-PVP. In all cases mixed micellar aggregates were formed and critical micellar concentrations of binary mixtures containing different mole frac-tions of the surfactants were measured using surface tension measurement. In the region where mixed micelles are formed, the interaction of two “normal ” surfactants and three “polymeric ” nonionic surfactants showed synergistic behavior and the results were analyzed using a interaction parame-ter, , which characterize the interaction in the mixed micelle and introduced by a regular solution theory. The regular solution theory can be applied to describe the interaction between TTAB and C12EO6, and graft polymeric surfactants systems. The results discussed in this paper showed reg-ular solution theory has broader extent of application. Keywords: 1