Interactions between amino acids and a cationic surfactant in binary solvent system

Abstract

The interaction of the cationic surfactant cetyltrimethylammonium bromide (CTAB) with amino acids (Lysine and Serine) in water and binary solvent combinations (Water-Ethyl Acetate) was studied conductometrically in this work. Solution formation method was used to study the effect of different parameters on interactions. Measured specific data were used to calculate the effect of temperature and concentration of added amino acids on the micellization of surfactant. Thermodynamic parameters for micellization i.e., Gibb's energy (ΔGm), and enthalpy (ΔHm), and entropy (ΔSm) have also been determined in presence of amino acids (Serine and Lysine). Results revealed that an increase in the concentration of added amino acids and binary solvent mixture (Ethyl Acetate-Water) causes an increase in critical micelle concentration (CMC) of CTAB where CMC of CTAB decreases with increasing temperature due to a decrease in hydrophobicity of molecules.