Effect of Alcohols on Phase Stability of Ionic Liquid Microemulsions

Pseudo-ternary phase diagrams of 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF 6 ) /Tween 80 (polyoxyethylene sorbitan monooleate)/alcohol/toluene systems were constructed with different linear-chain alcohols. The phase diagrams demonstrate that an increase in the surfactant/alcohol weight ratio yields a larger microemulsion domain. The different chain lengths of the alcohols affected the extent of the microemulsion region. Alcohols having short-chain lengths were optimum cosurfactants in bmimPF 6 -based microemulsion. Moreover, the influence on the microstructure of the single-phase area as a function of the alcohol chain was investigated using electrical conductivity. Preliminary investigations suggested that the bmimPF 6 -in-toluene region of systems which contain ethanol was notably magnified, and increasing in alcohol chain length (n = 4 – 10) led to a shrinkage for alcohols with longer chain length.