Polystyrene-Br End-Group Modification via Electrolysis: Adjusting Hydrogenation vs Coupling Selectivity.

Atom transfer radical polymerization (ATRP) enables the precise synthesis of polymers with well-defined architectures, controlled molecular weights, and low dispersity. However, the halogen end-groups inherent to ATRP polymers can pose challenges due to their chemical reactivity and thermal instability. To address these issues, various strategies, including chemical and photochemical methods, have been developed for chain-end modification.

Photo-RAFT Polymerization under Microwatt Irradiation via Unimolecular Photoinduced Electron Transfer.

Photoinduced radical addition fragmentation chain transfer (PET-RAFT) polymerization typically requires high light intensity (>5 mW/cm2), limiting energy efficiency and scalability. We demonstrate that adding a base to PET-RAFT systems drastically enhances the reactivity of acidic chain transfer agents (CTAs) with Zn-based photocatalysts (Zn porphyrin and Zn phthalocyanine). This approach enables complete polymerization under microwatt light intensity (0.