Aggregation behavior of Dioctadecyldimethylammonium chloride in mixed cationic surfactant system

The spontaneous formation of mixed vesicles, their coexistence and solubilization due to formation of mixed micelles were investigated for the double chain Dioctadecyldimethylammonium chloride (DODAC) and a single chain Dodecylethyldimethylammonium bromide (DDAB), mixed cationic surfactants. Various analytical techniques viz., conductivity, surface tension, fluorescence and absorption spectroscopy were utilized. To gain an insight into the mixed aggregate formed, thermodynamic free energy, molecular interaction parameter, the total critical micelle concentration and degree of ionization of the mixed micelle (alpha) as a function of molar ratio were assessed. Acoustic properties of the mixed surfactant system as functions of temperature were also calculated. Interaction of pyrene with mixed aggregates in the present system was assessed through fluorescence spectroscopy (at cvc as well as cmc) at 298.15 K and atmospheric pressure. (C) 2014 Elsevier B.V. All rights reserved.