2022 |
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Park, Jaemin; Nam, Jiyun; Seo, Myungeun; Li, Sheng Side-chain density driven morphology transition in brush−linear diblock copolymers Journal Article ACS Macro Lett., 11 (4), pp. 468-474, 2022, ISBN: 2161-1653. Abstract | BibTeX | Tags: Bottlebrush polymer Microphase separation Postpolymerization modification RAFT polymerization @article{Li2022, title = {Side-chain density driven morphology transition in brush−linear diblock copolymers}, author = {Jaemin Park AND Jiyun Nam AND Myungeun Seo AND Sheng Li}, url = {https://pubs.acs.org/doi/10.1021/acsmacrolett.2c00068}, doi = {10.1021/acsmacrolett.2c00068}, isbn = {2161-1653}, year = {2022}, date = {2022-04-19}, journal = {ACS Macro Lett.}, volume = {11}, number = {4}, pages = {468-474}, abstract = {We report the synthesis and self-assembly of brush–linear diblock copolymers with variable side-chain length and density. Poly(pentafluorophenyl acrylate-g-ethylene glycol)-b-polystyrene ((PPFPA-g-PEG)-b-PS) brush–linear diblock copolymers are prepared by sequential reversible addition–fragmentation chain transfer (RAFT) polymerization of PPFPA and PS, followed by postpolymerization reaction between the precursor PPFPA-b-PS diblock copolymer and amine-functionalized PEG. By controlling the PEG chain length and the degree of substitution, we obtained brush–linear diblock copolymers with different side-chain lengths and densities. The solid-state morphologies of the diblocks are then examined by small-angle X-ray scattering (SAXS). At low PEG side-chain density, the segregation of PEG and PS away from PPFPA leads to the formation of PEG and PS lamellar domains with PPFPA in the interface. At high PEG side-chain density, the segregation is between the PPFPA-g-PEG brush block and the PS linear block, and the domain morphology is determined by the composition of the brush block. A partial experimental phase diagram is presented, and it illustrates the importance of both side-chain length and density on the microdomain morphology of brush–linear diblock copolymers.}, keywords = {Bottlebrush polymer, Microphase separation, Postpolymerization modification, RAFT polymerization}, pubstate = {published}, tppubtype = {article} } We report the synthesis and self-assembly of brush–linear diblock copolymers with variable side-chain length and density. Poly(pentafluorophenyl acrylate-g-ethylene glycol)-b-polystyrene ((PPFPA-g-PEG)-b-PS) brush–linear diblock copolymers are prepared by sequential reversible addition–fragmentation chain transfer (RAFT) polymerization of PPFPA and PS, followed by postpolymerization reaction between the precursor PPFPA-b-PS diblock copolymer and amine-functionalized PEG. By controlling the PEG chain length and the degree of substitution, we obtained brush–linear diblock copolymers with different side-chain lengths and densities. The solid-state morphologies of the diblocks are then examined by small-angle X-ray scattering (SAXS). At low PEG side-chain density, the segregation of PEG and PS away from PPFPA leads to the formation of PEG and PS lamellar domains with PPFPA in the interface. At high PEG side-chain density, the segregation is between the PPFPA-g-PEG brush block and the PS linear block, and the domain morphology is determined by the composition of the brush block. A partial experimental phase diagram is presented, and it illustrates the importance of both side-chain length and density on the microdomain morphology of brush–linear diblock copolymers. | |
Kim, Ki Hyun; Nam, Jiyun; Choi, Jinwoong; Seo, Myungeun; Bang, Joona From macromonomers to bottlebrush copolymers with sequence control: synthesis, properties, and applications Journal Article Polym. Chem., 13 (16), pp. 2224-2261, 2022, ISBN: 1759-9954. Abstract | BibTeX | Tags: Block polymer Bottlebrush polymer Polymer synthesis @article{Bang2022, title = {From macromonomers to bottlebrush copolymers with sequence control: synthesis, properties, and applications}, author = {Ki Hyun Kim AND Jiyun Nam AND Jinwoong Choi AND Myungeun Seo AND Joona Bang}, url = {https://pubs.rsc.org/en/content/articlelanding/2022/py/d2py00126h}, doi = {10.1039/D2PY00126H }, isbn = {1759-9954}, year = {2022}, date = {2022-03-14}, journal = {Polym. Chem.}, volume = {13}, number = {16}, pages = {2224-2261}, abstract = {Bottlebrush polymers (BBPs) are a type of comb-like macromolecule with densely grafted polymeric sidechains attached to the polymer backbones, and many intriguing properties and applications have been demonstrated due to their unique architecture. Moreover, a ring-opening metathesis polymerization (ROMP) technique using Grubbs catalysts allows a precise control of various structural parameters in BBPs, such as the sidechain length, backbone length, and sidechain microstructures. This review mainly highlights recent advances of BBPs prepared by ROMP, from synthesis efforts to properties and applications.}, keywords = {Block polymer, Bottlebrush polymer, Polymer synthesis}, pubstate = {published}, tppubtype = {article} } Bottlebrush polymers (BBPs) are a type of comb-like macromolecule with densely grafted polymeric sidechains attached to the polymer backbones, and many intriguing properties and applications have been demonstrated due to their unique architecture. Moreover, a ring-opening metathesis polymerization (ROMP) technique using Grubbs catalysts allows a precise control of various structural parameters in BBPs, such as the sidechain length, backbone length, and sidechain microstructures. This review mainly highlights recent advances of BBPs prepared by ROMP, from synthesis efforts to properties and applications. | |
2019 |
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Nam, Jiyun; Kim, YongJoo; Kim, Jeung Gon; Seo, Myungeun Self-assembly of monolayer vesicles via backbone-shiftable synthesis of Janus core–shell bottlebrush polymer Journal Article Macromolecules, 52 (24), pp. 9484-9494, 2019, (selected as a Front Cover). Abstract | BibTeX | Tags: Block polymer Bottlebrush polymer RAFT polymerization ROMP Self-assembly @article{Nam2019, title = {Self-assembly of monolayer vesicles via backbone-shiftable synthesis of Janus core–shell bottlebrush polymer}, author = {Jiyun Nam and YongJoo Kim and Jeung Gon Kim and Myungeun Seo}, year = {2019}, date = {2019-12-10}, journal = {Macromolecules}, volume = {52}, number = {24}, pages = {9484-9494}, abstract = {We report the self-assembly of monolayer vesicles from Janus core–shell bottlebrush polymers. A route was developed to synthesize doubly grafted bottlebrush copolymers (DGBCPs) possessing A-b-B and B′-b-C side chains on a single repeating unit. Graft-through ring-opening metathesis polymerization of a norbornene moiety installed by single unit monomer insertion allowed us to place the backbone on any repeating unit of the core (B and B′) block. By decorating each core chain end with different chains via reversible addition–fragmentation chain transfer polymerization, we can obtain nanoobjects with an asymmetric B core and a phase-separated A/C shell. We demonstrate that polystyrene-branch-polystyrene′ and polylactide-b-polystyrene-branch-polystyrene′-b-poly(n-butyl acrylate) macromonomers can be successfully synthesized and polymerized to produce DGBCPs in high yields (81–94% conversion) with an absolute molar mass of 149–395 kg mol–1 and a dispersity of 1.18–1.38. In a solvent slightly more selective to A than C, self-assembly of monolayer vesicles with diameter of <100 nm was observed by transmission electron microscopy. Dissipative particle dynamics simulations suggest that increasing the backbone length and moving the backbone toward the B′/C interface increases the backbone bending energy and favors a lower curvature. The spontaneous curvature appears to prefer a particular layer radius, avoiding bilayer formation.}, note = {selected as a Front Cover}, keywords = {Block polymer, Bottlebrush polymer, RAFT polymerization, ROMP, Self-assembly}, pubstate = {published}, tppubtype = {article} } We report the self-assembly of monolayer vesicles from Janus core–shell bottlebrush polymers. A route was developed to synthesize doubly grafted bottlebrush copolymers (DGBCPs) possessing A-b-B and B′-b-C side chains on a single repeating unit. Graft-through ring-opening metathesis polymerization of a norbornene moiety installed by single unit monomer insertion allowed us to place the backbone on any repeating unit of the core (B and B′) block. By decorating each core chain end with different chains via reversible addition–fragmentation chain transfer polymerization, we can obtain nanoobjects with an asymmetric B core and a phase-separated A/C shell. We demonstrate that polystyrene-branch-polystyrene′ and polylactide-b-polystyrene-branch-polystyrene′-b-poly(n-butyl acrylate) macromonomers can be successfully synthesized and polymerized to produce DGBCPs in high yields (81–94% conversion) with an absolute molar mass of 149–395 kg mol–1 and a dispersity of 1.18–1.38. In a solvent slightly more selective to A than C, self-assembly of monolayer vesicles with diameter of <100 nm was observed by transmission electron microscopy. Dissipative particle dynamics simulations suggest that increasing the backbone length and moving the backbone toward the B′/C interface increases the backbone bending energy and favors a lower curvature. The spontaneous curvature appears to prefer a particular layer radius, avoiding bilayer formation. |