Combination of the Photoinduced Atom Transfer Radical Addition Reaction and Living Cationic Polymerization: A Latent Initiator Strategy toward Tailoring Polymer Molecular Weight Distributions

The polymer molecular weight distribution (MWD) has a vital impact on material properties. Here, we presented a convenient approach for controlling the MWD in batch polymerization by a latent initiator strategy, which is realized by the photocontrolled transformation from the latent initiator to the initiator during polymerization. A photoinduced atom transfer radical addition reaction and living cationic polymerization were combined in this method, which was further utilized to transform the mechanism from radical polymerization to cationic polymerization. In addition, this strategy was also demonstrated to be able to initiate living cationic polymerization from abundant organic halides. Poly(vinyl ether)s with controlled molecular weight and narrow MWD (<1.10) can be obtained under mild conditions such as room temperature and visible light. Polymers with bimodal and trimodal distributions were obtained easily through a convenient external photoswitch “on/off” operation, showing that this method is a useful tool for exploring the limits in tuning MWDs in batch polymerization.