Interaction of nonionic surfactants and hydrophilic ionic liquid in aqueous solutions

Abstract

ABSTRACT The interaction between an ethoxylated nonionic surfactant (C12-14 EO8) and three conventional hydrophilic imidazolium based ionic liquids (bmim-OctylSO4, bmim- MethylSO4, and bmim-BF4) in aqueous solution has been investigated. In most of the reported studies where a surfactant is dissolved in an ionic liquid aqueous solution, conventional ionic liquids are merely considered as solvents. Consequently, the resulting critical micelle concentration (cmc) is considered to be that of the surfactant. However, given that the three ionic liquids selected showed the typical shape of a surface active compound when the surface tension was plotted against concentration, the role of these compounds as ¿secondary surfactant¿ and consequently the possibility of mixed micelles formation has been suggested.