Journal of Chemical Thermodynamics, Vol.95, 15-20, 2016
Thermodynamics on the micellization of various pure and mixed surfactants: Effects of head- and tail-groups
The values of critical micelle concentration (CMC) for the micellization of various pure and mixed surfactants are determined by the UV-Vis spectrophotometric method. And the effects of temperature on the CMC values have been measured and thermodynamic parameters' values are calculated to analyse the effects of head-and tail-groups on the micellization of surfactant molecules. The results show that the values of Delta G degrees are negative and those of Delta S degrees are positive for the micellization of all the surfactants within the measured temperature range. But the values of Delta H degrees are positive or negative, depending on the kinds of surfactants. All these thermodynamic parameters' values are decreasing together with the increase of temperature for all the surfactants. And these thermodynamic parameters' values are depending severely on the chain length of alkyl group also as much as on the head-groups of surfactant molecules. (C) 2015 Elsevier Ltd. All rights reserved.