Poly(ethylene glycol)-b-poly(vinyl acetate) block copolymer particles with various morphologies via RAFT/MADIX aqueous emulsion PISA

The polymerization-induced self-assembly (PISA) of amphiphilic diblock copolymers of poly(ethylene glycol)-b-poly(vinyl acetate) (PEG-b-PVAc) in water was achieved through macromolecular design via interchange of xanthate (MADIX) polymerization in emulsion. Poly(ethylene glycol) with a dithiocarbonate (xanthate) end-group (PEG-X) was synthesized by post-modification of commercial poly(ethylene glycol). The chain extension of PEG-X was then conducted in water using vinyl acetate (VAc) to produce PEG-b-PVAc amphiphilic diblock copolymers. Their in situ self-assembly led to stable latex particles. The molar mass of the PVAc block was varied to trigger the formation of various morphologies including spheres, vesicles and large compound vesicles.