Effect of alkyl chain on micellization properties of dodecylbenzenesulfonate based surface active ionic liquids using conductance, surface tension, and spectroscopic techniques

Abstract

Two surface active ionic liquids (ILs) having 1-alkyl-3-methylimidazolium cationic moiety and dodecylbenzenesulfonate based anionic moiety i.e. [C5mim][DBS] and [C7mim][DBS], have been synthesized. 1H-NMR, thin layer chromatography were done for their characterization. These DBS-ILs have lower critical micelle concentration (CMC) in comparison with their conventional sodium dodecylbenzenesulfonate [Na][DBS] surfactants and hence are highly surface active. The conductance, surface tension, absorption (UV-visible) and emission (Fluorescence) techniques were used to determine the CMC values. DBS-ILs showed a remarkable absorption and emission spectra where intensity changes with variation in concentration of IL. Micelle self-assembly formation was also predicted by dynamic light scattering (DLS) technique. Conductance and surface tension techniques were employed to study the aggregation behavior in aqueous conditions. Various surface active parameters were evaluated at 298.15 K employing surface tension techniques. Conductance measurements were performed at three rising temperatures (288.15, 298.15, and 308.15) K and their thermodynamic parameters were calculated. From the above studies, the present synthesized ionic liquids found to have remarkable surface activity.