Evolution of Surface Tension and Hansen Parameters of a Homologous Series of Imidazolium-Based Ionic Liquids.

In this study, we systematically analyze the surface tension and Hansen solubility parameters (HSPs) of imidazolium-based ionic liquids (ILs) with different anions ([NTf], [PF], [I], and [Br]). These anions are combined with the classical 1-alkyl-3-methyl-substituted imidazolium cations ([CCIm]) and a group of oligoether-functionalized imidazolium cations ([(mPEG)Im]) based on methylated polyethylene glycol (mPEG). In detail, the influences of the length of the alkyl- and the mPEG-chain, the anion size, and the water content are investigated experimentally.