Induced Alterations in the Aggregation Behavior and Thermodynamic Properties of Anionic Surfactant Sodium Tetradecyl Sulfate (STS) in presence of Imidazolium Based Ionic Liquid in Aqueous Media: A Conductometric Study

Abstract

Surfactants can be considered as an important class of chemical species having a polar head and non-polar tail, which make it capable to be utilized in many industrial formulations such as coatings, paints, lubricants, and cosmetics, etc. Also, ionic liquids, which are actually molten salts, are also having many useful properties such as negligible vapor pressure, high thermal stability, etc. They can modify the physiological as well as aggregation properties of conventional surfactants according to our desire. The mixtures of ionic liquids with a surfactant are found to be better systems for many industrial applications than individual ones. Thus the micellization behavior of sodium tetradecyl sulfate STS is investigated in the presence of 1-propyl-3-methylimidazolium bromide [C3mim][Br] in aqueous media. For this, ionic liquid 1-propyl-3-methylimidazolium bromide [C3mim][Br] is synthesized in our lab. Then the conductivity measurement is done to determine the critical micelle concentration (CMC) of sodium tetradecyl sulfate STS in the absence and presence of (0.02, 0.05 and 0.1) wt. %, of 1-propyl-3-methylimidazolium bromide [C3mim][Br] in aqueous medium at three different temperatures i.e. (298.15, 303.15 and 308.15) K. The results are then utilized to find the thermodynamic parameters of micellization such as, standard free energy of micellization, standard enthalpy of micellization, and standard entropy of micellization, which are important to understand the driving force behind the process of micellization.