RAFT with Light: A User Guide to Using Thiocarbonylthio Compounds in Photopolymerizations

This perspective offers an in-depth guide to photopolymerizations mediated with thiocarbonylthio compounds, with a particular focus on photoiniferter and photoinduced energy/electron transfer RAFT (PET-RAFT) polymerizations, focusing on practical considerations. It is designed to provide both newcomers and experts with the practical knowledge needed to harness light-mediated polymerizations for innovative applications. The discussion begins with an overview of conventional RAFT polymerization and proceeds to highlight the distinctive advantages of the photomediated processes. The photochemical behavior of thiocarbonylthio compounds, along with the selection of appropriate light wavelengths, is critically examined for its impact on polymerization kinetics and optimization of polymer properties. Key parameters influencing polymerization success─such as catalyst selection, solvent choice, light intensity, and temperature─are explored in detail. The importance of oxygen tolerance and end-group fidelity is also addressed, as these factors are essential for achieving well-defined polymers. Additionally, reactor configurations are reviewed, focusing on the roles of light sources, reactor geometry (batch versus flow systems), and temperature control in optimizing the reaction efficiency. The article concludes by integrating these concepts into a comprehensive framework for optimizing photoiniferter and PET-RAFT polymerizations.