Effects of electrolytes on the surface and micellar characteristics of Sodium dodecyl sulphate surfactant solution

Abstract

The effect of some electrolytes (namely sodium acetate and calcium acetate) on their critical micelle concentration (CMC), have been determined by spectrophotometric, conductometeric and surface tension measurement method at 298K, 308K and 318K. From the surface tension data physico-chemical properties such as surface excess concentration (Γmax) and minimum area per molecule (Amin) at surface have been obtained. From the observed CMC data, free energy of micellization (∆Gmic), entropy change of micellization (∆Smic), and enthalpy change of micellizaton (∆Hmic) for the studied surfactant solutions with or without electrolyte have been obtained. The results have been interpreted in light of inter-molecular interaction.