Iterative evaluation of micellar and thermodynamic properties of 12-2-12 in 1 % BSA aqueous solution in the presence of organic solvents and temperature

Abstract

The interactions between a gemini surfactant 12-2-12 and bovine serum albumin (BSA) have been studied in aqueous and mixed aqueous media by conductance measurements using the iterative method at different temperatures ranging from 298.15 K to 313.15 K with step size 5. The critical micellar concentration (CMC) as well as the degree of ionization for the micelles (α) have been evaluated and their variation with solvent type and temperature has been discussed. The error for conductivity measurements was calculated and found to be much smaller than for surface tension measurements using the platinum ring method. The CMC values for the mixture of 12-2-12 and BSA in aqueous solvent solutions follow the sequence: DMF > AN > DMSO > water. These values were further confirmed by surface tension studies. From the thermodynamic parameters, hydrophobic interactions were found to be the driving force for micellization. The existence of enthalpy-entropy compensation was established from the linear plot of ΔH° m and ΔS° m .