Phase behavior of polymerized ionic liquid mixtures in a non-aqueous solvent

The formation of complex coacervates has been a subject of great interest in the field of charged polymers, with a focus almost exclusively on aqueous systems. Herein, we studied the phase behavior of two polymerized ionic liquids, namely poly(1-ethyl-3-methyl imidazolium (3-sulfopropyl) acrylate) and poly(1-(2-acryloyloxy-ethyl)-3-buthyl-imidazolium bis(trifluoromethane) sulfonimide), representing a polyanion and a polycation, respectively, in non-aqueous solutions. By controlling the concentration of the polymers and added salt composed of the two counterions, we studied the conditions for one vs. two phases, which provides useful information for further applications of polymerized ionic liquids, as well as providing an interesting comparison with the phase behavior of other charged polymers such as polypeptides and polysaccharides in aqueous media.