Topology Affecting Block Copolymer Nanoassemblies: Linear Block Copolymers Versus Star Block Copolymers Under Pisa Conditions

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.