Effect of organic additives and temperature on the micellization of cationic surfactant cetyltrimethylammonium chloride: Evaluation of thermodynamics

In the present study, we report the effect of organic additives and temperature on the micellization of cationic surfactant cetyltrimethylammonium chloride (CTAC). The micellization behavior of CTAC was studied at different fixed temperatures and fixed concentrations of organic additives (viz., sugar and amino acid) in aqueous solutions. The criticalmicelle concentrations (CMC) of CTAC were measured by the conductivity and dye solubilization methods. The CMC values first increase with increasing temperature (up to 298 K) and then decrease with increasing temperatures; whereas the increasing trend was found to be with organic additive concentrations. The thermodynamic parameters (viz., standard Gibbs energy (ΔG_m⁰), standard enthalpy (ΔH_m⁰), and standard entropy (ΔS_m⁰) of micellization of CTAC) are evaluated. The thermodynamic parameter values clearly indicate less stability of the CTAC solution in the presence of organic additives.