Metal-free near-infrared-induced radical-promoted cationic RAFT polymerization for high penetration photocuring

The application of cationic RAFT polymerization in photocuring has enabled the fabrication of stimuli-responsive materials. However, these systems mainly rely on UV light, limiting their broader applications. In this study, we introduce a metal-free, NIR-sensitive radical-promoted cationic RAFT polymerization system using IR-780 as the photocatalyst. The system offers excellent control over polymer molecular weights and narrow molecular weight distributions, enabling precise polymerization even under deep curing conditions. By employing a combination of cationic RAFT agents and NIR light, we achieve controlled polymerization of a range of vinyl ethers, demonstrating the versatility and efficiency of the approach. Additionally, the method is applied to photocuring applications, demonstrating its potential for fabricating complex 3D structures and welding applications. This work provides a strategy for deep photocuring with spatial and temporal control, expanding the potential applications of RAFT polymerization in biocompatible and large-scale manufacturing systems.