An Environmentally Benign and pH-Sensitive Photocatalyst with Surface-Bound Metalloporphyrin for Heterogeneous Catalysis of Controlled Radical Polymerization

Abstract

The implementation of photocatalysts for controlled/living radical polymerization upon visible light harvesting has emerged as a robust and powerful technique for the user-friendly synthesis of well-structured polymers with composition, spatiotemporal, and sequence control. Nevertheless, the incompatibility of present synthetic protocols with environmentally benign media, such as water, still poses a detrimental threat to their practical applications. In this article, the adoption of hPGM-ZnTPP hollow microspheres with pH sensitivity and excellent dispersibility in various reaction media, which are firmly immobilized yet accessible catalytic metalloporphyrin components as heterogeneous photocatalysts for the photoinduced electron/energy transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization, was demonstrated. Modulation of solution pH affected the performance of the catalysts, with the faster polymerization rate being observed in basic conditions rather than in acidic conditio...