Study on the Polarity of bmimPF₆/Tween80/toluene Microemulsion Characterized by UV-Visible Spectroscopy

Abstract

With the aid of nonionic surfactant Tween80, the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF₆) forms nonaqueous microemulsions with toluene. The phase diagram of the ternary system was prepared at 25°C. It was demonstrated that there were a single-phase region and a two-phase region in the ternary phase diagram. The single-phase region could be further divided into toluene-in-bmimPF₆, bicontinuous and bmimPF₆-in-toluene microemulsion regions by electrical conductivity. And by the use of methyl orange as an absorption probe, the polarity of the bmimPF₆-in-toluene microemulsion was probed by UV-vis spectroscopy. A relatively constant polarity of the microemulsion droplets is obtained in the bmimPF₆ microemulsion.

Keywords:

• Ionic liquid
• microemulsion
• Tween80
• UV-vis spectroscopy

Acknowledgments

The authors are grateful to the “XIBUZHIGUANG” Science Foundation of the Chinese Academy of Sciences for their financial support.