Poly(ionic liquid)s: Polymers expanding classical property profiles

In recent years, polymeric/polymerized ionic liquids or poly(ionic liquid)s (PILs) were found to take an enabling role in some fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the flexibility and properties of macromolecular architectures and provide novel properties and functions that are of huge potential in a multitude of applications, including solid ionic conductor, powerful dispersant and stabilizer, absorbent, precursor for carbon materials, porous polymers, etc. So far, the preparation of PILs with various forms in cations and anions has mostly focused on the conventional free radical polymerization of IL monomers. Recent progress in the preparation of PILs via controlled/“living” radical polymerizations points out an unprecedented opportunity to precisely design and control macromolecular architecture of IL species on a meso-/nanoscale within a polymer matrix. There are also newly emerging polymerization techniques that have appeared for the preparation of PILs which have further pushed the limit of the design of PILs. In this review, we try to summarize the current preparative strategies of PILs, providing a systematic and actual view on the polymer chemistry behind. A discussion of the properties and applications of PILs constitutes the second part of this review.