Switching from Single to Simultaneous Free‐Radical and Anionic Polymerization with Enamine‐Based Organic Electron Donors

Although most monomers can polymerize through different propagation pathways, polymerization‐initiating systems that can switch from one mode to another are rare. In this study, we demonstrate that enamine‐based organic electron donors (OEDs) constitute the first systems able to initiate either free‐radical or anionic polymerization under simple, mild, and safe conditions. While direct electron‐transfer reduction of monomers by OEDs results in the initiation of anionic chain‐growth polymerization, introduction of a competing oxidant with a higher reduction potential than the monomer switches the former anionic propagation to a clean radical‐propagation process. The benefit of this dual‐mode activator is highlighted in the synthesis of an interpenetrating polymer network through simultaneous initiation of radical and anionic propagation processes. Organic electron donors (OEDs) act as dual‐mode activators priming concomitant radical and anionic polymerizations to prepare interpenetrating polymer networks. OEDs can simultaneously reduce an oxidant to initiate a radical propagation and reduce a monomer to initiate an anionic propagation. These light‐, metal‐, and peroxide‐free redox systems open new horizons for the development of macromolecular architectures through dual chain‐growth modes.