Photo-controllable cationic homopolymerization and random copolymerization of vinyl ethers based on iridium salt photocatalyst

Temporal control of chain growth is a central challenge for photoinitiated active polymerization. In this work, we introduced an iridium salt complex-based catalyst system to achieve fine temporal control of the chain growth process. By electrochemical analysis, compared with the pyran salt photocatalyst, it was found that the iridium salt complex could promote the chain transfer of active species to reversible addition-fragmentation chain transfer polymerization (RAFT) reagent, thereby generating dormant species, which provided the possibility of time control of the polymerization process. Using this catalytic system, we successfully achieved homopolymerization of vinyl ethers with different substituents and random copolymerization with isobutyl vinyl ethers, which is not only pointed the way for broadening the monomer selection in the future, but also provided an innovative way to prepare new functionalized materials. Iridium complexes catalyze photocontrolled cationic polymerization of alkyl vinyl ether under blue led illumination. image