液晶表面锚定能的温度依赖性研究

通过测量扭曲液晶盒中的液晶分子的实际扭曲角及摩擦方向与液晶分子的界面指向矢之间的方位偏角，用自行建立的液晶方位表面锚定能的测量方法，测定了５ＣＢ液晶与摩擦的聚酰亚胺界面的锚定能及其温度依赖性，并用热力学理论进行了分析．实验结果表明，随着温度的增加液晶的表面锚定能Ｅ_ａ是减小的，从２５.５℃时的５.０×１０^－5Ｊ／ｍ²减小到３５℃时的５.０×１０^－6Ｊ／ｍ²；同时，外推长度ｄ_e随 关键词：

INVESTIGATION OF THE TEMPERATURE DEPENDENCE OF SURFACE ANCHORING ENERGY FOR LIQUID CRYSTALS

The surface anchoring of nematic liquid crystals is an important coefficient which expresses the effect of liquid crystal alignment and the mechanism of the surface alignment. The surface azimuthal anchoring energy can be obtained by measuring the twist angle in the twist cell and the surface torsional angle between the rubbing direction and the liquid crystal director at the substrate boundary. The temperature dependence of the surface anchoring energy at 5CB-polyimide (PI) interface was studied. The surface anchoring energy decreases with increase of the temperature from ５.０×１０^－5Ｊ／ｍ² at 25.５℃ to ５.０×１０^－6Ｊ／ｍ² at 35.0℃. Meanwhile, the extrapolation length ｄ_e increases from 80nm at 25.5℃ to ３７０ｎｍ at ０.５℃ below Ｔ_c. This result clearly signifies the important role of the ordered structure of the nematic interface in determining the temperature dependence of the anchoring strength at the ５ＣＢ-PI interface.