Sulfonated Polymerized Ionic Liquid Block Copolymers

The successful synthesis of a new diblock copolymer, referred to as sulfonated polymerized ionic liquid (PIL) block copolymer, poly(SS‐Li‐b‐AEBIm‐TFSI), is reported, which contains both sulfonated blocks (sulfonated styrene: SS) and PIL blocks (1‐[(2‐acryloyloxy)ethyl]‐3‐butylimidazolium: AEBIm) with both mobile cations (lithium: Li+) and mobile anions (bis(trifluoromethylsulfonyl)imide: TFSI−). Synthesis consists of polymerization via reversible addition‐fragmentation chain transfer, followed by post‐functionalization reactions to covalently attach the imidazolium cations and sulfonic acid anions to their respective blocks, followed by ion exchange metathesis resulting in mobile Li+ cations and mobile TFSI− anions. Solid‐state films containing 1 m Li‐TFSI salt dissolved in ionic liquid result in an ion conductivity of >1.5 mS cm−1 at 70 °C, where small‐angle X‐ray scattering data indicate a weakly ordered microphase‐separated morphology. These results demonstrate a new ion‐conducting block copolymer containing both mobile cations and mobile anions. Successful synthesis of a sulfonated polymerized ionic liquid (PIL) block copolymer, a new block copolymer, which contains both sulfonated blocks and PIL blocks with both mobile cations (lithium: Li+) and mobile anions (bis(trifluoromethylsulfonyl)imide: TFSI−) is reported.