Aggregation behaviour of cationic (cetyltrimethylammonium bromide) and anionic (sodium dodecylsulphate) surfactants in aqueous solution of synthesized ionic liquid [1-pentyl-3-methylimidazolium bromide] -Conductivity and FT-IR spectroscopic studies

Abstract

Current study includes the conductivity and spectroscopic study of the cationic surfactant cetyltrimethylammonium bromide (CTAB), and anionic surfactant sodium dodecylsulphate (SDS), in aqueous solutions of ionic liquid 1-pentyl-3-methylimidazolium bromide [C5mim][Br] at different temperatures T=(298.15, 308.15, 318.15) K. Obtained experimental data of conductivity have been utilize to determine the critical micellar concentration (CMC) i.e. concentration at which the self-assembly of amphiphilic molecules take place, also the effect of temperature on CMC have been studied. Critical micelle concentration has been utilized to calculate the thermodynamic parameters such as, standard enthalpy of micellization (ΔHm0), standard free energy of micellization (ΔGm0), and standard entropy of micellization (ΔSm0). Results obtained from thermodynamic parameters has been discussed in terms of structural changes occurred in the system. Work is mainly concerned with the influence of ionic liquid 1-pentyl-3-methylimidazolium bromide [C5mim][Br] on the micellization process of the cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulphate (SDS) at below CMC, CMC and above CMC. Alterations produced in the structure of the mixtures (surfactants and aqueous solutions of ionic liquids) have been discussed by FT-IR Spectroscopic studies.