An Inimer Approach Based on Photo Iniferter RAFT Polymerization Toward One-Pot Bottlebrush Copolymers Featuring Grafts From Less Activated Monomers

Photo iniferter reversible addition–fragmentation chain transfer (PI-RAFT) polymerization offers a versatile route to complex macromolecular architectures including bottlebrush copolymers. Here, a chemo selective inimer strategy that exploits the differences in propagating radical stability of more activated monomers (MAMs) and less activated monomers (LAMs) is presented. This approach focuses on the reactivity matching of such propagating radicals and the chain transfer agent (CTA) R-group radical. Conditions including the wavelength of the light source and chemical structures of the CTA and monomers have been systematically assessed within this experimental work. An acrylamide-based RAFT inimer bearing a primary R-group xanthate (TRISXan) was polymerized under blue light to produce a polymeric backbone containing active grafting sites. Subsequent switch to UV irradiation enabled controlled grafting of NVF/NVP side chains, yielding bottlebrush copolymers through a one-pot, two-step process. The results demonstrate that combining wavelength selectivity with monomer-dependent CTA reactivity provides a versatile route that enables the production of more complex polymers, extending the scope of PI-RAFT polymerization to systems that include both MAMs and LAMs.