Shuichi Matsui

Novel Liquid Crystalline Four Ring Chain Difluoromethyleneoxy Compounds for Quicker Response LC Mixtures

A series of chemically stable novel liquid crystalline four ring chain compounds (1a–1c) having a difluoromethyleneoxy (CF2O) linkage moiety have been designed and prepared, and their properties have been thoroughly investigated. The novel compounds intrinsically possess much higher positive Δϵ (>32) and Δn (>0.190), relatively low viscosity, wider nematic phase temperature ranges and significantly higher clearing temperatures in comparison to the analogous three ring chain CF2O compound (2) that is currently applied in almost all the latest TN-TFT monitors, notebook PCs and IPS-TVs.

Series of LC compound containing polar conjugated terminal groups

A homologous series of various compounds with polar terminal groups conjugated with carbon-carbon double bonds: the cyanoethylene, cyanobutadiene, and fluorocyanoethylene groups were prepared. These derivatives have very wide mesomorphic temperature ranges. Moreover, by measuring physical properties, the mixtures containing this series were found to have large dielectric anisotropies and appropriate birefringence values. The x-ray diffraction measurement of the cyanoethylene derivatives supports an anti parallel dimer conformation in their smectic phases. A fluorine atom at the (alpha) position of the cyano group prevents the formation of such electrostatic dimers. It is concluded that the wide mesomorphic temperature range of these derivatives was caused by the stronger molecular interaction. Moreover, the derivatives which can form dimer structures showed the wider mesomorphic temperature ranges.