Interaction of an Acid Functionalized Magnetic Ionic Liquid with Gemini Surfactants

Abstract

The micellar properties of two Gemini surfactants i.e., butanediyl-1,4-bis(dimethyldodecyl ammonium bromide (C12-4(OH)2-C12,2Br−) and butanediyl-1,4-bis(dimethyldohexylammonium bromide) (C16-4-C16, 2Br−) in the presence of an imidazolium based acid functionalized magnetic ionic liquid (IL) i.e., 1-acyl-3-methylimidazolium tetrachloroferrate [AcMIm]FeCl4, are studied using various techniques such as surface tension, conductivity, fluorescence and FT-IR spectroscopy. The surface adsorption parameters and thermodynamic parameters are systematically determined. The critical micelle concentration (CMC) is decreased and surface tension of CMC (γcmc) values are increased significantly in the presence of different wt% of the added IL, and the values are observed in the order as 0.07 > 0.05 > 0.02 > water. In this study, the Gibbs energy of adsorption (ΔG ads o ) value was found to be greater than the Gibbs energy of micellization (ΔG m o ), showing that adsorption is more favored in aqueous Gemini surfactant systems. The FT-IR spectral results further confirm the changes produced by the magnetic IL [AcMIm]FeCl4 on aqueous solutions of C12-4(OH)2-C12,2Br− and C16-4-C16,2Br−. It is noteworthy that increasing the wt% of [AcMIm]FeCl4 results in an increase in the spontaneity of CMC formation on Gemini surfactants and the IL has more affinity for C16-4-C16, 2Br− compared to C12-4(OH)2-C12,2Br−.