Conductometric and spectroscopic studies of sodium dodecyl sulfate in aqueous media in the presence of organic chalcogen

The effect of the addition of the organic chalcogen (Py2Se2) on the micellization of Sodium dodecyl sulfate (SDS) in aqueous solution was studied using spectroscopic and electrical conductivity techniques. UV–vis spectroscopy, nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) were employed to get information regarding the interaction between the surfactant and additive aggregates and the mechanism of docking of the surfactant and the additive molecules in the system. The system has been investigated in terms of concentration and temperature variation for conductometric studies. The conductivity data were used to determine the critical micelle concentration (cmc) and degree of counter ion binding (β) in the temperature range 288.15–323.15 K. The free energy (ΔGm°), enthalpy (ΔHm°) and entropy (ΔSm°) of micellization were determined using the temperature dependence of cmc. The calculated thermodynamic parameter |TΔSm| is larger than |ΔHm|, which indicates that the micellization is entropy driven.