2023 Fiscal Year Final Research Report
Novel liquid crystalline compounds: the phase transition mechanism of calamitic-discotic bimesomorphism
| Project/Area Number |
19K05630
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 35030:Organic functional materials-related
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| Research Institution | Nara Institute of Science and Technology |
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Principal Investigator |
Shimizu Yo 奈良先端科学技術大学院大学, 先端科学技術研究科, 特任教授 (40357223)
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| Co-Investigator(Kenkyū-buntansha) |
河合 壯 奈良先端科学技術大学院大学, 先端科学技術研究科, 教授 (40221197)
内田 欣吾 龍谷大学, 理工学部, 教授 (70213436)
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Keywords | 液晶相転移 / カラミチック液晶 / ディスコチック液晶 / 分子変形 / スメクチック相 / ディスコチック相 / トリフェニレン / アゾベンゼン |
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| Outline of Final Research Achievements |
A triphenylene derivative wth six alkoxyazobenzene units (linked by propylene ester group) is the first example of liquid crystal which exhibits a calamitic -discotic bimesomorphic phase transition as a single component system. The mechanism of SmA-Colr mesophase transition was studied with two different anisotropic samples by synchrotron radiation X-ray diffraction measurements to reveal that in the phase transition of SmA to Colr phases, alkoxyazobenzen units are shifted in a rotational manner around a triphenylene ring to cause the transformation of molecular shape from rod-like to disc-like ones. In addition, the corresponding ether analogue as the linkage part which is more flexible than ester linkage were synthesized and studied on the mesomorphic phase transition behavior. The dodecyl homologue shows 6 mesophases, though the corresponding ester analogue does only three mesophases to indicate an importance of the flexibility of linkage group for the mesopmorphism.
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| Free Research Field |
液晶材料化学
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| Academic Significance and Societal Importance of the Research Achievements |
カラミチックーディスコチック双液晶性を示すトリフェニレン（円盤状部位）のアルキル長鎖アゾベンゼン（棒状部位）６置換体（結合基はプロピレンエステル基）が示すスメクチックA（SmA）相―レクタンギュラーカラムナー（Colr）相転移のメカニズムが解明されたことにより、それぞれの部位が互いにどのように振る舞うことで分子全体としてコンフォメーション変化を通した分子変形が生じそれが双液晶性の発現に繋がったかが判明した。このことは、よりダイナミックな分子集合系としての液晶系研究に新たな視座を提供できたと考える。
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