Masatoshi Matsuda

Novel Columnar Liquid-Crystalline Nanomaterials Designed toward Anhydrous Organic Proton Conductors

Urea derivative with double long alkyl chains and the corresponding rare-earth metal complex were prepared and their thermotropic liquid-crystalline behavior was evaluated by differential scanning calorimetry, polarizing optical microscopy, X-ray diffractometry, electron microscopy. It was found that in spite of the compounds without disk-like molecular shape, they exhibit a columnar phase with two-dimensional rectangular lattice in which each column is built up from one-dimensional molecular chains, i.e., non-covalently linked polymer architectures on the basis of one-dimensional hydrogen bond. In the columnar liquid-crystalline materials, we predicted that delocalization of protons along the one-dimensional self-assembled molecular chains is induced, resulting in useful channels for prototropy. To verify this prediction, we evaluated preliminarily the electric conductivity of the urea liquid-crystalline thin films by electrochemical impedance spectroscopy. The solid-state films retaining a columnar structure showed a protonic conductivity even under dry conditions.

Chain-Folding Conformations in Isotactic Polypropylene.

α型イソタクチックポリプロピレンのchain-foldingの構造について考察した. 結晶の (100) 面および (140) 面における分子鎖のfold部分のコンホメーションを, 分子動力学および分子力学計算によって求めた. fold部分のエネルギーはfold部分のプロピレン連鎖数が3個ごとに極小値をとる周期性を示した. fold部分でらせんの巻き方向が反転する様子を主鎖炭素原子の二面角の変化として表した. この結果, 結晶格子中のらせんの巻き方向とメチル基の上下の向きの規則性を満足しながら, コンホメーションの変化のみで分子鎖が折りたたまれている様子を明示できた.