Influence of iso-perthiocyanic acid and temperature on the aggregation properties of sodium dodecylsulphate in dimethylsulphoxide

Abstract

This paper investigates the effect of a heterocyclic compound, iso-perthiocyanic acid (IPA) (0.01, 0.05, and 0.10mol∙kg−1) on the micellization behavior of sodium dodecylsulphate (SDS) (1–52mmol∙kg−1) in dimethylsulphoxide (DMSO) by employing three conventional techniques viz. conductivity, density, and speed of sound measurements over a wide temperature range (293.15–313.15K). From all the techniques, the critical micelle concentration (CMC) values have been determined, and the results have been discussed in terms of SDS-IPA solvophobic and hydrogen bonding interactions in DMSO. The temperature dependence of the CMC values has proved the dominance of disruption of structured DMSO molecules around the alkyl chain of SDS. Further, the XCMC values have been used to calculate the standard thermodynamic parameters of micellization like enthalpy (ΔHmo), free energy (ΔGmo), and entropy (ΔSmo). The density and speed of sound data have been used to evaluate the volumetric and compressibility parameters like apparent molar volume (ϕv), isentropic compressibility (Ks), and apparent molar isentropic compression (ϕκ) to get more clear insight with regards to solute–solute / solute–solvent interactions existing in the present SDS–IPA–DMSO ternary system. In addition, an attempt has also been made to examine the antifungal activity of IPA in combination with SDS in aqueous medium.