2004 Fiscal Year Final Research Report Summary
Liquid crystalline polymers with banana mesogens-Polarity and chirality induced by their banana shape
| Project/Area Number |
15350130
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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 |
Polymer/Textile materials
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
WATANABE Junji Tokyo Institute of Technology, Department of Polymeric and Organic Materials, Professor, 大学院・理工学研究科, 教授 (90111666)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAUTI Susumu Tokyo Institute of Technology, Department of Polymeric and Organic Materials, Assistant Professor, 大学院・理工学研究科, 助手 (80204676)
TOKITA Masatoshi Tokyo Institute of Technology, Department of Polymeric and Organic Materials, Assistant Professor, 大学院・理工学研究科, 助手 (30301170)
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| Project Period (FY) |
2003 – 2004
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| Keywords | banana molecule / ferroelectricity / chirality / chiral conformation / frustrated structure / polymeric effect / smectic liquid crystal / bent molecule |
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| Research Abstract |
Liquid crystalline compounds with non-linear molecular shape, so-called banana-shaped molecules, have become a fruitful topic in liquid crystal researches since ferro-, anti-ferroelectricity and chrality were found in such achiral moleculear systems. A number of banana-shaped liquid crystalline molecules have been synthesized and studied by particularly modifying of the well-known banana-shaped molecule 1,4-phenylene [4-(4-n-alkoxypheny liminomethyl)benzoates, P-n-O-PIMB, subsequently, a variety of liquid crystalline phases and interesting properties have been revealed. In this study, we prepare a new homologous series of banana-shaped molecule containing oxadiazole core,2,5-bis(4'-n-alkylcarboxy biphenyl-4-yl)-[1,3,4]-oxadiazole (ODBBP-n) to extend the study on the polymeric banana molecules. To our knowledge, this is the first example of five-membered heterocyclic liquid crystalline molecule that exhibits banana class mesophase. In addition, the relationship between the bending geometry and mesomorphic behavior of ODBBP-n is also demonstrated by comparing with thiaziazole core derivatives. The results obtained simply described below.
1)From the analysis of chiral memory between B2 and B4 phases, it was concluded that the spontaneously arising chirality is due to the chiral conformation characteristic of the banana shape.
2)In ferroelectric B2 phase, the distinct layer undulation takes place as a result of the interplay between the spontaneous polarization and layer elasticity.
3)In the banana molecules with the asymmetric alkyl tails, it was found that antiferroelectric phase is altered to the ferroelectric phase when two tail groups have the remarkable difference in their length.
4)The extension of the study to the polymeric system failed because of the high temperature melting of polymer. Now, we try to synthesize the dimer and trimer of banana molecules.
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