Oxygen-Tolerant, Controlled Synthesis of Degradable and Water-Soluble Poly(Vinyl Amide)s via Radical Ring-Opening Copolymerization of Cyclic Dithiothreitol.

Radical ring-opening polymerization (rROP) has emerged as a powerful strategy for introducing degradable linkages into vinyl polymer backbones. In this study, we report an oxygen-tolerant photoinduced electron/energy transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization approach for the synthesis of degradable copolymers from cyclic dithiothreitol (cDTT) and a broad range of technologically relevant N-vinyl monomers, as well as other less activated monomers. This method gives access to well-defined copolymers with predictable molecular weights, low dispersities, and efficient cDTT incorporation. Degradable polymers were accessed using low cDTT feed ratios (2-10 mol%), enabling the preparation of materials with compositions dominated by the parent vinyl monomers while presenting multiple cleavable sites along the backbone. The incorporated cDTT generates disulfide, thioaminal, and vicinal diol functionalities, thereby enabling backbone degradation under reductive, acidic, and oxidative conditions. Despite the low cDTT content employed, which limits the extent of reductive cleavage, periodate-mediated oxidation enabled efficient and rapid backbone degradation. This work expands the scope of cyclic disulfides as comonomers in rROP and provides a practical route to degradable vinyl materials based on widely used N-vinyl species.