Influence of tetra ethyl ammonium bromide (C2H5)4NBr on the aggregation behavior of surface active ionic liquid 1-tetradecyl-3-methylimidazolium bromide [C14mim][Br

Abstract

In this work, we tend to explore the effect of organic electrolyte i.e. tetra ethyl ammonium bromide (C2H5)4NBr on the aggregation behavior of 1-tetradecyl-3-methylimidazolium bromide [C14mim][Br] by utilizing electrical conductivity measurement, refractive index measurement, UV–Visible spectroscopy as well as FT-IR spectroscopic study. First of all, the synthesis of [C14mim][Br] is carried out in the laboratory, then the critical micelle concentration (CMC) of [C14mim][Br] is determined using conductivity measurements at temperatures 298.15 K, 308.15 K and 318.15 K in the absence and presence of (C2H5)4NBr at different concentrations 1 mM, 2 mM and 5 mM. The reduction in value of CMC is observed with respect to increasing concentration of (C2H5)4NBr and with the increase in temperature, the value of CMC also increases. These results are observed due to the establishment of reinforced hydrophobic interactions between the hydrophobic parts of surface active ionic liquid and the electrolytes. Then we reflected different thermodynamic parameters such as, standard free energy of micellization (ΔGm0), standard enthalpy of micellization (ΔHm0), and standard entropy of micellization (ΔSm0) in the temperature range 298.15 K–318.15 K, utilizing the value of CMC obtained from conductivity measurements. A graphical contrast of these thermodynamic parameters has been made. Further refractive index measurement and UV–visible spectroscopic study have been employed to verify the CMC obtained using conductivity measurement, which is found to be very close to that obtained via conductivity study. The alterations produced in the respective system have been confirmed via FT-IR spectroscopic study, which signify the variations produced by electrolyte on the aggregation of surface active ionic liquid in aqueous media.