Akihiko Sugimura

The nature of the orientational relaxation process of the director, (n) over cap, to its equilibrium orientation, (n) over cap (eq)(r), in a liquid crystal cell has been investigated both experimentally and theoretically. The experiments employ deuterium NMR spectroscopy to investigate the time-resolved field-induced director orientation, and the theory is based on a numerical study of the system of hydrodynamic equations; these include both director motion and fluid flow and take account of backflow. The relaxation time and the influence of the effect of backflow on the orientational relaxation process for a thin nematic film of 4 - n - pentyl -4' - cyanobiphenyl has been investigated for a number of dynamic regimes. Reasonable agreement is observed between the calculated values and experimental results.

Due to the amphiphilicity nature of glycolipids, some are known to exhibits liquid crystals phases both in thermotropic and lyotropic phases. Six different glycolipids have been synthesized using three steps process and their structures have been characterized by H-1-NMR and C-13-NMR in acetylated and deacytelated forms. Their liquid crystals properties were studied using optical polarising microscopy (OPM) and differential scanning calorimetry (DSC). The effect of alpha-methylated tails is compared with those of the straight chain glycolipids. The epimeric effect of the hydroxyl group at the C-4 of the sugar group was also commented. (C) 2010 Published by Elsevier B.V.

The cell gap dependence of the pretilt angle of a parallel cell has been evaluated for the first time：the smaller the cell gap，the smaller the pretilt angle. Experimental results were accounted for by a mathematical modeling of the dependence of the surface anchoring energy on the cell gap．

種々の表面アンカリングエネルギ条件下での液晶セル内ダイレクタ分布を、理論的実験的に調べた。実験には、重水素化したネマチック液晶を用いた核磁気共鳴法を用いている。本実験では、液晶セルへの強磁場印加に加えて、可変電界を重複印加することにより、セル内での全トルク制御を行っている。実験により得た共鳴スペクトルを、弾性理論に基づくダイレクタ分布解析により明らかにした。