液晶性色素の塗布膜における光学異方性に対するせん断流動の影響

抄録

The effect of shear flow on an optical anisotropic film of chromonic liquid crystal by use of applicator was investigated. Some chromonic dyes form a rod like aggregation in an aqueous solution and change to a chromonic liquid crystal in a certain concentration and temperature of the solution. When the chromonic liquid crystal is applied to a glass substrate by an applicator, the aggregates in the chromonic liquid crystal are oriented in one direction in the thin film, and it exhibits an optical anisotropy such as birefringence and dicrhoism. The orientation process of the aggregates during application, however, is still unknown in detail. The application process, especially shear region, was considered to be important to make the optical anisotropy film having a uniform and high dichroism. The shear flow would have the multi-domain collapsed and transformed to mono-domain. In the present experiment, small texture disappeared when the chromonic liquid crystal under the shear flow was observed by microscope, however the optically measured dichroism and birefringence by the laser did not vary even though the shear rate changed widely. The birefringence is ten times larger at the exit of applicator, which is elongation region, than the one just under the applicator. The shear flow shows limited effectiveness against the molecular orientation. It would be the elongation flow that is more effective to produce a good optical anisotropic film.