Krafft temperature and thermodynamic study of interaction of glycine, diglycine, and triglycine with hexadecylpyridinium chloride and hexadecylpyridinium bromide: A conductometric approach

Krafft temperature (Tk) and thermodynamics of micellization of Hexadecylpyridinium chloride (HPyCl) and Hexadecylpyridinium bromide (HPyBr) were carried out in the absence and in the presence of amino acids-glycine, diglycine and triglycine. Thermodynamic parameters of micellization - Gibbs free energy of micellization, enthalpy, entropy, free energy related with hydrophobic part and surface contribution were calculated from the specific conductance data. Transfer values of Gibbs free energy and enthalpy were also calculated. Tk of HPyCl and HPyBr were determined in aqueous as well as in presence of aqueous-glycine, diglycine and triglycine. Effect of polar head group, counter-ions, additives, Tk, and micellization parameters on micelle formation of the surfactants are the main points taken into consideration while explaining and interpreting the results to get an insight into the interactions of these additives with the cationic surfactants.