Copper-Chelated Thermoresponsive Polymer Nanocatalysts for Fenton-Like Reactions

Self-assembled nanostructures containing functional metal chelating sites have been of great interest for developing artificial enzyme-like smart nanocatalysts. To achieve such functional soft materials, promising approaches have been demonstrated with stimuli-responsive polymers due to their chemically tunable structures, which can be engineered to incorporate a wide range of functionalities in a facile manner. Herein, we present Cu-chelated hybrid polyionic complex (HPIC) core/shell-type nanostructures that exhibit thermoresponsive catalytic activity for Cu-catalyzed Fenton-like reactions with enhanced efficiency and selectivity for specific substrate molecules. Incorporation of 20% NiPAAm into the Cu-chelated core allowed for temperature-sensitive control of catalytic activity, while the shell-forming pPEGMA exhibited cloud points much lower than the known LCST, which enabled reversible flocculation of nanocatalysts for facile recycling without significant loss of catalytic activity. These results demonstrate that metal-chelated HPIC nanostructures of thermoresponsive copolymers can be employed as attractive smart materials for catalytic nanoplatforms.