Star amphiphilic block copolymers: synthesis via polymerization-induced self-assembly and crosslinking within nanoparticles, and solution and interfacial properties

The star amphiphilic block copolymer of star-[poly(N-isopropylacrylamide)-block-polystyrene] [s-PNIPAM-b-PS] is synthesized via RAFT polymerization by combining polymerization-induced self-assembly (PISA) and crosslinking within the linear block copolymer nanoparticles. This strategy affords convenient synthesis of star s-PNIPAM-b-PS with a high molecular weight and a narrow molecular weight distribution. This star s-PNIPAM-b-PS exists as dispersed nanospheres in both common solvents and block-selective solvents, and the size of star s-PNIPAM-b-PS nanospheres is not seriously affected by the polymer concentration, which is different from that of the linear poly(N-isopropylacrylamide)-block-polystyrene [PNIPAM-b-PS] block copolymer counterpart. The solution properties, thermoresponse and interfacial properties of star s-PNIPAM-b-PS are investigated, which were found to be significantly different from those of linear PNIPAM-b-PS.