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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Engineering / Faculty of Engineering >
Peer-reviewed Journal Articles, etc >
Rod-coil type miktoarm star copolymers consisting of polyfluorene and polylactide : precise synthesis and structure-morphology relationship
| Title: | Rod-coil type miktoarm star copolymers consisting of polyfluorene and polylactide : precise synthesis and structure-morphology relationship |
| Authors: | Saito, Kengo Browse this author | | Isono, Takuya Browse this author | | Sun, Han-Sheng Browse this author | | Kakuchi, Toyoji Browse this author | | Chen, Wen-Chang Browse this author | | Satoh, Toshifumi Browse this author →KAKEN DB |
| Issue Date: | 2015 |
| Publisher: | Royal Society of Chemistry |
| Journal Title: | Polymer chemistry |
| Volume: | 6 |
| Issue: | 39 |
| Start Page: | 6959 |
| End Page: | 6972 |
| Publisher DOI: | 10.1039/c5py01031d |
| Abstract: | A series of rod-coil miktoarm star copolymers consisting of poly[2,7-(9,9-dihexylfluorene)] (PF) and polylactide (PLA) arms as the rod and coil segments, respectively, were synthesized by combining the chain-growth Suzuki-Miyaura coupling polymerization and living ring-opening polymerization (ROP). First, PFs having a hydroxyl group at the alpha-chain end (PF-BnOH) were prepared by the polymerization of 2-(7-bromo-9,9-dihexyl-9H-fluorene-2-yl) 4,4,5,5-tetramethyl-1,2,3-dioxaborolane using the initiating system of 4-(tetrahydropyran-2'-yloxymethyl)-iodobenzene/Pd-2(dba)(3)/t-Bu3P. After a couple of chain end modifications, PFs having one, two, and three hydroxyl groups at the alpha-chain end (PF-OH, PF-(OH)(2), and PF-(OH)(3), respectively) were obtained with dispersity (D) values of less than 1.29. The obtained PF-OH, PF-(OH)(2), and PF-(OH)(3) were used as the initiators for the organic base-catalyzed ROP of rac-lactide to produce the AB type linear diblock (PF-b-PLA) and AB(2) and AB(3) type miktoarm star copolymers (PF-b-(PLA)(2) and PF-b-(PLA)(3), respectively). The self-assembled nanostructures in the thermally-annealed PF-b-(PLA)(x)s (x = 1, 2, and 3) were evaluated in the bulk by synchrotron small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The PF-b-PLA, PF-b-(PLA)(2), and PF-b-(PLA)(3) with the PF weight fractions of 0.52-0.56 were found to form poorly ordered PLA cylindrical structures in the PF matrix due to a strong rod-rod interaction of the PF segment. On the other hand, these BCPs with the PF weight fractions of 0.22-0.23 exhibited the hexagonally close-packed cylinder (Hex) morphologies, in which the cylindrical PF phase was embedded in the PLA matrix. More interestingly, the domain-spacing (d) values for the Hex morphologies decreased with the increasing PLA arm number despite each BCP having a comparable molecular weight and PF weight fraction: d = 26.4 nm for PF-b-PLA, d = 21.7 nm for PF-b-(PLA)(2), and d = 18.6 nm for PF-b-(PLA)(3). |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/62643 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 佐藤 敏文
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