RAFT Dispersion Copolymerization of Styrene and N-methacryloxysuccinimide: Promoted Morphology Transition and Post-Polymerization Cross-Linking

Polymerization-induced self-assembly (PISA) is an efficient and robust strategy to fabricate polymeric nano-objects. PISA enables us to prepare polymeric nano-objects in situ during the course of polymerization in concentrated solution (up to 50% w/w), making industrial production of polymeric assemblies in large-scale possible. In this work, reversible addition-fragmentation chain transfer (RAFT) dispersion copolymerization of styrene (St) and N-methacryloxysuccinimide (NMAS) was conducted with poly(2-hydroxyethyl acrylate) (PHEA) as a macro-chain transfer agent (macro-CTA) in methanol. Compared with the PHEA-mediated alcoholic dispersion polymerization of St, RAFT dispersion copolymerization of St and NMAS promoted morphology transition of nano-objects to form higher order morphologies (such as worms and vesicles). Moreover, the introduction of NMAS units into the solvophobic blocks provided functional handles for post-PISA modification of the resultant nano-objects via the active ester-amine reaction. The reaction of 1,6-hexanediamine with NMAS units in P(St-co-NMAS) blocks was conducted to afford cross-linked nano-objects with robust structural stability.