2001 Fiscal Year Final Research Report Summary
| Project/Area Number |
11450369
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子構造・物性(含繊維)
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
HASEGAWA Hirokazu Kyoto University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (60127123)
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| Co-Investigator(Kenkyū-buntansha) |
SAIJO Kenji Kyoto University, Graduate School of Engineering, Technician, 工学研究科, 教務職員 (60115847)
TAKENAKA Mikihito Kyoto University, Graduate School of Engineering, Instructor, 工学研究科, 助手 (30222102)
HASHIMOTO Takeji Kyoto University, Graduate School of Engineering, Professor, 工学研究科, 教授 (20026230)
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| Project Period (FY) |
1999 – 2001
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| Keywords | block copolymer / polymer blend / bicontinuous structure / Gyroid / single crystal / grain / sponge / electron microscopy |
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| Research Abstract |
Gyroid is a kind of thermodynamically stable bicontinuous microdomain structures observed for microphase-separated structures of block copolymer systems. Gyroid structure of block copolymers is characterized by the Gyroid minimal surface given by differential geometry and forms a complex and highly regular quasi-crystalline lattice. Bulk samples are usually consisting of many grains that are the regions where the microdomain structure has a. single orientation, and it is the case also for Gyroid. However, if we can have a single-grain Gyroid or a Gyroid single crystal, it would be very useful for the application as a functional material. In this research work, we aimed to produce large Gyroid single crystals by utilizing the self-organization process of block copolymer/homopolymer blends, and succeeded to clarify the following results
In the casting processes of polystyrene-block-polyisoprene diblock copolymer/ homopolystyrene blends from solution, the self-organizing processes of Gyroi
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d grains are divided into two cases : (i) sponge, an irregular network structure, transforms into Gyroid, and (ii) HPL(hexagonally perforated layer) transforms into Gyroid. In the former case, sponge is formed first from the disordered phase, and the morphological transition involves expelling of excess homopolystyrene from Gyroid phase because sponge contains more homopolymer than Gyroid. Since the nucleation of Gyroid structure occurs in many places, coagulation and reorganization of Gyroid grains take place during the Gyroid growth. The homopolymer and sponge structures sandwiched between coagulated Gyroid grains tend to be kept inside the Gyroid grains as the lattice defects. In the latter case, sponge is formed first from the disordered phase as well. However, it transforms into HPL immediately and then the HPL transforms into Gyroid. In such a case, the number density of Gyroid grains is very small and coagulation of Gyroid grains would not occur. Therefore, Gyroid single crystals with few lattice defects are formed Less
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