Here, the author summarizes recent development of stimuli-responsive synthetic polymers in ionic liquids (ILs) as a novel platform in designing intelligent soft materials. Owing to the versatile structure designability and unique properties of ILs, such as nonvolatility and wide liquid temperature range, soft materials consisting of polymer–IL combinations can be employed under an open atmosphere for long term, and can also permit wide operating temperature and pressure conditions without concern for solvent evaporation that has been a serious drawback of traditional soft materials.
