Interconvertible living radical and cationic polymerization through reversible activation of dormant species with dual activity.

The polymerization of vinyl monomers generally requires the selection of an appropriate single intermediate, whereas in copolymerization, the selection of the comonomer is limited by the intermediate. Herein, we propose interconvertible dual active species that can connect comonomers through different mechanisms to produce specific comonomer sequences in a single polymer chain. More specifically, two different stimuli, that is, a radical initiator and a Lewis acid, are used to activate the common dormant C-SC(S)Z group into radical and cationic species, thereby inducing interconvertible radical and cationic copolymerization of acrylate and vinyl ether to produce a copolymer chain that consists of radically and cationically polymerized segments. The dual reversible activation provides control over molecular weights and multiblock copolymers with tunable segment lengths.