Topology Affecting Block Copolymer Nanoassemblies: Linear Block Copolymers versus Star Block Copolymers under PISA Conditions

Abstract

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.

Scalable preparation of alternating block copolymer particles with inverse bicontinuous mesophases

“…The particle morphology of amorphous BCPs is determined by the relative block ratio and interfacial area according to the packing parameter p = V/a 0 l c ( V the volume of the core-forming block, a 0 the interfacial area, and l c the length of the core-forming block) 9 . While packing parameter reflects the geometry of the particles, many parameters have been demonstrated to influence the morphology, including the solubility parameter 10,11 , the incompatibility between BCPs 12 , topology 13–15 , and others 16 . BCP particles have been widely produced using solution self-assembly approach that has recognized limitations of multistep processing and low concentration 17,18 .…”

Hierarchical self-assembly of miktoarm star copolymers with pathway complexity

“…Similarly, amphiphilic star copolymers, including block copolymer stars 40 and miktoarm stars, 41 can also self-assemble in selective solvents to generate micellelike aggregates. [42][43][44][45][46][47][48][49][50][51] Notably, the resulting micellar structures are much more complicated than those formed by linear block copolymers. For example, star block copolymers can self-assemble into nanoparticle clusters 42 and lacunal 43 and bicontinuous nanospheres.…”

Functionalization and metathesis polymerization induced self-assembly of an alternating copolymer into giant vesicles

“…[2][3][4][5] However, PISA is mostly constructed from polymers bearing amphiphilic AB diblocks or ABC triblocks, which requires tedious multistep syntheses and sometimes require the preparations of elaborately designed small molecules and solvent selectivity, and so forth. [6][7][8] Acyclic diene metathesis (ADMET) polymerization, on the other hand, has also been considered to be an efficient route for the construction of nanomaterials. Advantages such as using a single type of a,u-diene monomer, the absence of side reactions and trans conguration of the metathetically generated double bonds make ADMET attractive for synthesis of defectfree, high-molecular-weight, all-trans polyolens.…”