Linear and star block copolymer (BCP) nanoassemblies of [poly(4-vinylpyridine)-block-polystyrene] n ([P4VP-b-PS] n ) with different arm numbers have been synthesized by RAFT dispersion polymerization under formulation of polymerization-induced self-assembly (PISA). All RAFT dispersion polymerizations employing mono-and multifunctional macromolecular chain transfer agents proceed with similar polymerization kinetics. The size and/or morphology of [P4VP-b-PS] n nanoassemblies are firmly correlative to arm number n, and star [P4VP-b-PS] n BCPs have more complex morphology than the linear counterpart. Several interesting morphologies of star BCPs including small-sized vesicles and porous nanospheres have been synthesized, and they are compared with those of the linear counterpart. Our research indicates that topology is a significant parameter to dedicate the size and morphology of star BCP nanoassemblies under PISA conditions.

Well-defined multi-arm star thermoresponsive block copolymer nano-assemblies of [poly(N-isopropylacrylamide)-block-polystyrene]n [(PNIPAM-b-PS)n] with n = 1, 2, 3 and 4 arms were synthesized by RAFT dispersion polymerization via polymerization-induced self-assembly.

A new method to modulate RAFT dispersion polymerization by introducing solvophilic homopolymers into the polymerization medium is proposed. It is discovered that in RAFT dispersion polymerization employing poly­(4-vinylpyridine) trithiocarbonate macro-RAFT agent, the introduced solvophilic homopolymers of poly­(N,N-dimethyl­acrylamide) (PDMA), poly­(ethylene glycol), and poly­(4-vinylpyridine) can greatly change both the size/morphology of poly­(4-vinyl­pyridine)-block-polystyrene nanoassemblies and polymerization kinetics. RAFT dispersion polymerization decelerates with the increasing amount of introduced PDMA, and it favors formation of complex block copolymer nanoassemblies in the presence of PDMA. The possible reason for introduced solvophilic homopolymers affecting polymerization kinetics and the block copolymer nanoassemblies is discussed. Adding solvophilic homopolymers into the polymerization medium is believed to be a promising alternative to modulate RAFT dispersion polymerization.

Linear and star thermo-responsive polymers of poly(N-acryloylsarcosine methyl ester) [(PNASME)n] and poly(N-isopropylacrylamide) [(PNIPAM)n] with arm number n = 1, 2, 3 and 4 were synthesized following a core-first method via solution RAFT polymerization employing a series of mono- and multi-functional chain transfer agents.

A photo-, temperature- and pH-responsive diblock copolymer containing a rigid spiropyran moiety was synthesized and its micellization was investigated.

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