Interaction between tetradecyltrimethylammonium bromide and benzyldimethylhexadecylammonium chloride in aqueous/urea solution at various temperatures: An experimental and theoretical investigation

The mixed micelle formation between tetradecyltrimethylammonium bromide (TTAB) and benzyldimethylhexadecylammonium chloride (BDHAC) has been investigated in the absence as well as attendance of urea using conductivity technique. The evaluated values were examined in accordance with Rubingh model. The obtained values of critical micelle concentration (cmc) were smaller than cmc(id) values suggesting attractive interactions between the constituents of solution. The micellar mole fractions (X-1(Rub)) of BDHAC, estimated by Rubingh model, were always higher than their ideal values (XV) suggesting the high contributions of BDHAC in mixtures of TTAB and BDHAC. Interaction parameter (beta) value was found to be negative showing an attractive interaction between the studied components. Activity coefficients (f(1)(Rub), and f(2)(Rub)) were always smaller than one in all cases and it indicates the attractive interaction between TTAB and BDHAC. The values of Delta G(m)(0) are found to be negative in all the cases which indicate the spontaneous formation of micelle. The values of Delta H-m(0), are negative in all cases indicating the exothermic process. The values of Delta S-m(0) are positive in case of aqueous medium and 500 mmol.kg(-1) urea solutions but found to be negative in attendance of 1000 mmol.kg(-1) urea. The values of excess free energy of micellization (Delta G(ex)(Rub)) were also estimated and achieved to be negative showing the stability of mixed micelles. (C) 2017 Elsevier B.V. All rights reserved.