摘要
向列液晶表面锚定是表征基板表面取向效果的关键参数,也是研究液晶分子表面取向排列机理的重要信息.描述向列液晶的表面锚定能首先要准确地理解对基板-向列液晶界面的宏观处理和微观处理的差异,其次要明确吉布斯(Gibbs)分界面的意义,它同表面锚定能与预倾角的热力学性质是同等重要的。向列液晶的表面锚定能可分为极化表面锚定能和方位表面锚定能两大类.人们已经采用多种实验技术从宏观上测试了向列液晶的表面锚定能。本文以热力学理论为基础,探讨了向列液晶表面锚定能的物理意义,并且以Freedericksz转变、高电场技术为例分析了极化表面锚定能的测试原理,以高磁场、Cano劈技术为例分析了方位表面锚定能的测试原理,最后用Cano劈技术给出了我们对外推长度的实验测试结果,并估算了液晶的表面锚定能的量级.
Surface anchoring of nematic liquid crystals is an important coefficient which express the effect of the liquid crystal alignment and studies the machenism of the surface alignment for nematic liquid crystals. Conceptual basis of the anchoring energy is first clarified by making a distinction between the macroscopic and the microscopic approaches toward the substrate-nematic interface, and the singnificance of the Gibbs' diving surface is emphasized together with some ther-modynamic properties of the anchoring energy and pretilt angle. The surface anchoring energy may be divided into two parts: polar and azimuthal anchoring. By surface thermodynamic theory, this paper studies the physical singnificance of the anchoring energy, analyses measurmental principle of the polar anchoring energy with two examples-high electric field and Freedericksr transition techniques, also it analyses measurmental principle of the azimuthal anchoring energy with two examples-high magnetic field and Cano wedge techmiques. For example, the extrapolation length of the 5CB-polyimide interface has been measured by Cano wedge technique and the numberical scale of the anchoring energy has been counted.
出处
《液晶通讯》
CAS
1993年第2期1-13,共13页
