Influence of an anionic hydrotrope on thermophysical properties of an anionic surfactant sodium dodecyl sulfate

Abstract

Herein we report micellization behavior of anionic surfactant, sodium dodecyl sulfate (SDS) in presence and absence of anionic hydrotrope (1,3-Benzenedisulfonic acid disodium salt (BDS)) in aqueous medium. Critical micelle concentrations (CMC) of mixed surfactant-hydrotrope systems were determined by conductometric technique. CMC values of surfactant-hydrotrope decrease with increasing hydrotrope concentration. Interactions between hydrotrope and surfactant are synergistic in nature. We also deduced thermodynamic parameters of micellization (viz., ΔG°m, ΔH°m, and ΔS°m). The effect of hydrotrope and temperature on different thermophysical properties have been discussed. Experimental techniques like FT-IR and NMR were employed to reveal the non-covalent interactions of mixed surfactant-hydrotrope systems.