In Situ Synthesis of Block Copolymer Nanoassemblies via Polymerization-Induced Self-Assembly in Poly(ethylene glycol)

A new formulation of polymerization-induced self-assembly in poly(ethylene glycol) (PEG) named PEG-PISA to synthesize diblock copolymer nanoassemblies via macromolecular RAFT agent mediated dispersion polymerization is reported. In PEG-PISA, the viscous PEG with molecular weight ranging from 200 to 1000 Da is used as polymerization medium. The utilization of the viscous PEG as the polymerization medium affords the advantages including, fast polymerization rate, good control over the synthesis of diblock copolymers, and in situ synthesis of both amphiphilic and doubly hydrophobic diblock copolymer nanoassemblies at polymer concentration of up to 50%. Also ascribed to the viscous polymerization medium of PEG, two new and/or interesting diblock copolymer nano assemblies of ellipsoidal vesicles and nanotubes are formed via PEG-PISA, and the reason on formation of ellipsoidal vesicles and nanotubes is discussed. The proposed PEG-PISA is anticipated to be an effective method to synthesize block copolymer nanoassemblies combining the advantages of alcoholic/aqueous PISA and versatility of poly(ethylene glycol).