Study of mixed micelles of Sodium dodecyl sulphate and nonionic surfactants polysorbates tween series:Their interaction and thermodynamic parameter using cyclic voltammetry

Abstract

Mixed micellar systems of anionic surfactant sodium dodecyl sulphate and nonionic surfactants polyoxyethylene sorbitan fatty acid esters (polysorbates) such as tween 20 /tween 40/tween 60 /tween 80 have been studied by using cyclic voltammetry, Surface Tension and Conductivity measurements. Critical micellar concentration values have been determined for various micellar systems by using cyclic voltammetry measurements using K4Fe(CN6) and KCl as an electroactive probe at 25 °C. Diffusion Coefficient has been computed from the peak current of the solution. Interaction parameter β has been calculated from regular solution theory. The negative values of interaction parameter suggest the synergistic behavior of all binary surfactant systems used in present study. Thermodynamic parameter free energy of micellization (ΔG°m) computed for various mole fraction of tween series. Decrease in ΔG°m with addition of tween series suggest spontaneous micellization.