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"デ・ヴリースのような"特性を有する液晶の設計:SmAとSmCを促進する要素の間の不満
Jeffrey C Roberts1, Nadia Kapernaum, Qingxiang Song
1Chemistry Department, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Journal of the American Chemical Society
|December 10, 2009
まとめ
新しいオルガノシロキサンメソゲンが合成され",デ・ヴリース様"の液晶特性を得られ,相変化の際に層の収縮が最小限に示された. これらの材料は,既定のデ・ヴリースの材料と比べて,低指向順と高転向順を示しています.
科学分野:
- マテリアルサイエンス 材料科学
- 液晶は,液体クリスタルです.
- 有機化学 オーガニック・ケミストリー
背景:
- デ・ヴリースのような液晶は,SmA-SmC相移行時に層の収縮が最小限 (<1%) である.
- このような材料の設計には,相応のフェーズプロモーション構造要素のバランスをとる必要があります.
- オルガノシロキサンは,液晶設計のための多用途のプラットフォームを提供します.
研究 の 目的:
- デ・ヴリーズのような性質を持つ新種のオルガノシロキサンメソゲンを合成し,特徴づけること.
- 分子構造と液晶相行動の関係を調査する.
- 既存のデ・ヴリス材料の代替品として,これらの新しい材料の潜在能力を評価する.
主な方法:
- オーガノシロキサンメソゲンの2つの同類系を合成する.
- 微角X線散射 (SAXS) は,温度の関数としてスメクティック層の距離 (d) を測定する.
- 光学的に傾斜角度を測定する.
- 還元因数 (Rとf) と熱膨張の分析.
主要な成果:
- メソゲン3 (n) は,0.5%から1.4%の層収縮でSmA-SmC相移行を示した.
- SmC相における負の熱膨張が観察され,傾きによる層収縮を相殺した.
- 化合物3 (n) は,低オリエンテーション順と高い翻訳順を示し,これはデ・ヴリースのような行動と一致している.
- 還元因数 (R) は,既定のド・ヴリーズ材料と同等またはそれより低いものでした.
結論:
- 合成されたオルガノシロキサンメソゲンは,デ・ヴリースのような有望な特性を示しています.
- 観測された性質は,構造要素のバランスと負の熱膨張に起因する.
- これらの材料は,高度な液晶アプリケーションのための新しいクラスの潜在的な候補を代表しています.
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