Polymerizable ionic liquids and polymeric ionic liquids: facile synthesis of ionic liquids containing ethylene oxide repeating unit via methanesulfonate and their electrochemical properties

Abstract

Polymeric ionic liquids have shown great potential in numerous application fields, and an easy access to polymerizable monomer is the key to the polymerized ionic liquids. The polymerizable monomer is usually synthesized via the quaternization of a corresponding bromide, which is usually prepared from bromination of the corresponding alcohol but with a low yield. In this study, a polymerizable monomer was prepared by quaternization of a mesylate, derived from the corresponding alcohol, followed by an ion exchange reaction. The polymerizable ILs M1–M4 showed ionic conductivity as high as 10⁻³ S cm⁻¹, and the oxygen effect was observed with the lithium salt. Polymeric ionic liquids P1 and P2 were prepared via radical polymerization on M1 and M2, and the ionic conductivity of polymeric ionic liquid P2 was as high as 2.2 × 10⁻⁴ S cm⁻¹ with electrochemical stability exceeding 7 V (vs. Li/Li⁺).