STUDIES ON SURFACTANT─SURFACTANT AND SURFACTANT─BIOMOLECULE INTERACTION.

We investigated the solubilization and co-solubilization of triphenyls (TPs) viz., triphenylphosphine (TPP), triphenylphosphineoxide (TPPO), triphenylammine (TPA) and triphenylmethanol (TPM) in various single and binary surfactant systems at 25 o C using spectrophotometry and HPLC. The solubilization capacity was found to be a function of locus of solubilization, nature and structure of solubilizate, aggregation number and the nature of interactions between the solubilizate and the micelles. The solubility of TPs follows the order TPPO > TPP > TPA in nonionic surfactants and TPPO > TPA > TPP in ionic systems, which was in direct corroboration with their locus of solubilization. In co-solubilization, competition between the TPs for the same solubilization sitestrongly affects the extent of co-solubilization. Regular Solution Approach (RSA) was used to evaluate the effect of surfactant mixing on the solubilization of TPs. The enhancement of TPs solubility in mixed micelles was ascribed to the structural micellar changes associated with the surfactant mixing. Comparative assessment of solubility descriptors, MSR and Km, was evaluated and the two were found to be different . Moreover, the kinetic aspects of TPP were investigated in different single and binary surfactant systems inthelight of the importance of TPP in organic reactions. The rate of reaction was found sensitive to different microenvironments provided by different regions of a micelle and hence strongly affected by the locus of solubilization of TPP in micelles