RAFT‐Mediated Emulsion Polymerization‐Induced Self‐Assembly for the Synthesis of Core‐Degradable Waterborne Particles

Poly(N‐acryloylmorpholine) (PNAM)‐decorated waterborne nanoparticles comprising a core of either degradable polystyrene (PS) or poly(n‐butyl acrylate) (PBA) were synthesized by polymerization‐induced self‐assembly (PISA) in water. A PNAM bearing a trithiocarbonate chain end (PNAM‐TTC) was extended via reversible addition‐fragmentation chain transfer (RAFT)‐mediated emulsion copolymerization of either styrene (S) or n‐butyl acrylate (BA) with dibenzo[c,e]oxepane‐5‐thione (DOT). Well‐defined amphiphilic block copolymers were obtained. The in situ self‐assembly of these polymers resulted in the formation of stable nanoparticles. The insertion of thioester units in the vinylic blocks enabled their degradation under basic conditions. The same strategy was then applied to the emulsion copolymerization of BA with DOT using a poly(ethylene glycol) (PEG) equipped with a trithiocarbonate end group, resulting in PEG‐decorated nanoparticles with degradable PBA‐based cores. Emulsion copolymerization of dibenzo[c,e]oxepane‐5‐thione (DOT) with either styrene or n‐butyl acrylate was carried out in water to produce block copolymer nanoparticles via RAFT‐mediated PISA in emulsion. Hydrophilic blocks are either poly(N‐acryloylmorpholine) or poly(ethylene glycol), two polymers largely used for their known biocompatibility. The degradability of the hydrophobic core block is ensured by in‐chain cleavable thioester functions.