Double hydrophilic diblock copolymers containing a poly(ionic liquid) segment: Controlled synthesis, solution property, and application as carbon precursor

In this contribution, we demonstrate the controlled synthesis of double hydrophilic block copolymers comprising a hydrophilic poly(ionic liquid) (PIL) segment via the RAFT/MADIX process. The non-ionic segment is made up from either poly(N-isopropylacrylamide) (PNIPAAm) or poly(N,N-dimethylacrylamide) (PDMA), due to their favorable controllable solubility in water at room temperature. They were employed as macro-chain transfer agents (macro-CTAs) for the RAFT polymerization of four different 1-vinylimidazolium ionic liquid monomers possessing different alkyl substitutes and anions. The block copolymers of PNIPAAm-b-PIL are dual stimuli-responsive copolymers that can respond to the changes in temperature and ionic strength in aqueous solution. This special property facilitated a facile anion exchange of the PIL segment. In addition, one copolymer could successfully be employed as carbon precursor for the preparation of mesoporous graphitic nanostructures in the presence of metal salts.