Amphiphilic Copolymer-Based Multichannel Toolbox with Multistage Adjustable and Visualized Catalytic Properties

Multiple responsive polymers have attracted increasing attention for a wide range of applications including nanocarriers and nanocomposite catalysts. Herein, an amphiphilic block copolymer P(NIPAAm-r-CA)-b-PMMA was synthesized by reversible addition-fragmentation chain-transfer polymerization with coumarin units embedded in the side chain. Followed by a reduction of the terminal group to hydrosulfonyl, relatively stable polymer microspheres can be prepared after self-assembling, and those microspheres could be further employed as carriers of gold nanoparticles (Au NPs) due to the strong interrelationship between -SH and Au. The polymer microspheres with Au NPs decorated onto the surface were endowed with reversible catalytic properties by adjusting temperature and UV irradiation owing to the introduction of photo-responsive coumarin units and thermo-responsive poly(N-isopropyl acrylamide) segments. Moreover, the catalytic performance could be retained even after several cycles of photo- or thermo-responsive regulation. Importantly, the fluorescence of the smart polymer under different pH values was studied to clarify the mechanism of emission, laying a necessary foundation for further visualization of the catalytic process.

Automated summary

The synthesis of amphiphilic block copolymers with embedded coumarin units and their application as carriers for gold nanoparticles have enabled reversible catalytic properties regulated by temperature and UV irradiation, providing a foundation for visualizing the catalytic process.