The interaction Study of Binary mixture containing Biosurfactant of sodium cholate and anionic surfactant of sodium dodecyl sulfate using conductometric technique

In this study, the micellization behavior of the sodium cholate (SCH) and sodium dodecyl sulfate (SDS), in aqueous solution in pure state, and mixture of them (SCH + SDS) in different mole fractions were investigated by conductometric method at 298.15 K. The obtained data from experimental measurements were used to determination of the critical micelle concentration (CMC) of surfactants in pure and mixed state. Also according to Regular Solution Theory (RST), were calculated the following parameters: the interaction parameter between surfactants in the mixed system (), activity coefficient (،), mole fractions of the components in the mixed micelle (,) and thermodynamic parameters such as Gibbs free energy of micellization () and excess free energy (). The results obtained show that in the anionic-anionic mixture, the interaction parameter is low and the activity coefficients show a small deviation from the ideal state, the standard Gibbs free energy of micellization () are negative values, this shows that the micelle formation process take place spontaneously.