Photo-Iniferter RAFT Synthesis of Versatile, Nonalternating Poly(acrylate-co-isocyanides)

Nonalternating poly(isocyanide-co-acrylate) copolymers enable access to novel polymer microstructures with versatile chemistry and allow for designed mechanical properties, an important facet of combating the plastic waste crisis. While previous syntheses used cobalt-mediated radical polymerizations, the cobalt complex exhibits side reactivity, complicating control over polymerization. This work describes the application of an orthogonal, photocontrolled RAFT polymerization to a range of isocyanides with excellent temporal control. Under solvent-free conditions, adding monomers with a standard chain transfer agent (CTA) results in the synthesis of copolymers that are then transformed into several novel microstructures. Interestingly, we discover that the isocyanide units can undergo cyclization of the backbone, resulting in an unexampled polyamide-like copolymer containing the pyrrolidone ring. Moreover, we generate poly(acrylic acid)-like copolymers with small amounts of ketone linkages through hydrolysis, enabling faster degradation rates for this class of polymer.