Functional star polymers via living radical polymerization-designer functional nanospaces

Abstract

This comprehensive article summarizes our recent efforts to design functional star polymers via living radical polymerization as functional nanospaces for catalysis and molecular recognition. Metal-bearing star polymer catalysts are efficiently obtained from the ruthenium-mediated linking reaction of arm polymers in the presence of a ligand monomer. Star polymer catalysts (nanoreactors) were effective for oxidation of sec-alcohols, (asymmetric) hydrogenation of ketones, and living radical polymerization, performing activity, stability, functionality-tolerance, and practicability (catalyst recycle, easy product recovery) higher than conventional polymer catalysts and analogues of in-core metal complexes. Core-functionalized star polymer nanocapsules selectively capture and stimuli-responsively release functional molecules. The key is to condense functional groups such as poly(ethylene glycol) (PEG), perfluoroalkane, and quaternary ammonium groups into the cores. Single-chain star polymers are created as a new class of star polymers via the self-folding of amphiphilic random copolymers with intramolecular hydrophobic interaction in water.