Activating ATRP Initiators to Incorporate End-Group Modularity into Photo-RAFT Polymerization

Heterogeneous photocatalysis is increasingly used in reversible deactivation radical polymerization (RDRP). In this study, we found that alkyl bromide redox chemistry typically found in atom transfer radical polymerization (ATRP) can be incorporated in concert with dithiocarbonyl disulfide chemistry into the reversible addition-fragmentation chain transfer (RAFT) process via bismuth oxide photocatalysis. This amalgamation of mechanisms introduces end-group modularity-a new layer of control-into RAFT polymers uniquely enabled by photoredox catalysis. We found that a diversity of functionality can be installed at the alpha-end group via alkyl bromides, while the molecular weight distribution can be tuned seamlessly at the omega-end group through the simultaneous addition of multiple disulfides.