(217u) Polymerized Ionic Liquid Block Copolymers Prepared By Thiol-Click Chemistry

Polymerized ionic liquids (PILs) have been proposed for gas separation membranes and battery electrolytes. However, in order to be processed into thin free standing films the glass transition temperature must be sufficiently high, which in in turn reduced gas permeability and ion conductivity. To overcome this limitation we have prepared PIL block co-polymers where a structural poly(methyl methacrylate) block provides structural integrity, and a low Tg (-50 degrees Celsius)PIL block provides ionic content. Our synthetic approach utilizes a protected thiol monomer that can be easily polymerized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Thio-Michael click chemistry is then used to conjugate functionalized ionic liquids to the diblock copolymer. This extremely modular approach allows rapid exploration of a number of different ionic liquid cations (triazolium, imidazolium, and phosphonium) from a single series of polymers.  Free standing films cast from these materials showed nanoscale phase separation, and promising properties for post combustion carbon capture.