柱状の液晶で,柱状の軸に沿って自発的な偏りがある

Daigo Miyajima¹, Fumito Araoka, Hideo Takezoe

¹School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.

Journal of the American Chemical Society

|June 10, 2010

まとめ

新しい扇形状の分子が,自発的偏化で液晶に自己組織化します. この極性メソフェーズは,強力な第2ハーモニック生成信号を含むユニークな光学特性を有しています.

科学分野:

超分子化学超分子化学
マテリアルサイエンス材料科学
液体結晶は,液体結晶から成る.

背景:

分子自己組み立ては,高度な材料の作成の鍵です.
液晶は固体状態と液体状態の間のユニークな相を示します.
柔らかい材料におけるマクロスコープの偏振は,達成するのが難しい.

研究の目的:

扇形状の分子を設計・合成し,自己組織化することができる.
自己組み立て材料の液晶性質を調査する.
極性メソフェーズの光学特性,特に第2ハーモニック生成 (SHG) を探求する.

主な方法:

水素結合アミド群と極性芳香核を持つ扇形状の分子の合成.
X線屈折や顕微鏡などの技術を用いて自己組み立て構造の特徴化.
柱状軸に沿ったマクロスコピック偏振の測定.
段階移行中の第2ハーモニック生成 (SHG) の光学測定.

主要な成果:

扇形状の分子は,柱状の液体結晶メソフェーズに自己組織化します.
このメソフェーズは,柱状軸に沿って前例のない自発的なマクロスコプ的偏振を示しています.
極性メソフェーズは,第2ハーモニック生成 (SHG) 信号の有意な発生を示している.
SHG信号は,イソトロップ性溶融への移行時に消えるが,冷却時に回復する.

結論:

特定の機能群を持つ扇形状の分子は,極性液晶相を形成することができる.
液晶における自発的なマクロスコープの偏振は,分子設計によって達成できます.
観測されたSHG信号は,メソフェーズの極性性質と,非線形光学アプリケーションのための潜在能力を確認しています.

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