Quantitative measurement and control of surface orientation energy of liquid crystal molecule on solid surfaces

阐明液晶在固体表面上的表面排列对于物理问题和器件应用具有重要意义，人们对此进行了各种各样的研究。然而，表面取向强度或锚定能尚未明确。本基金主要针对这一问题进行了研究，取得了以下成果：阐明了一种测量表面涂覆聚合物并用布摩擦的基材表面对准强度（锚定能）的方法。2. 采用上述新方法研究了摩擦强度对锚固能的影响。结果表明，锚固能与摩擦密度直接相关。此外，还建立了一种可靠、准确的表面能控制方法。3. 研究了上述方法控制的表面锚定能对铁电液晶分子取向的影响。结果表明，通过将锚定能降低到一个临界值以下，成功地形成了铁电液晶理想的均匀排列（书架结构），从而实现了具有微秒级快速响应和优异存储特性的电光器件。4. 支配锚定能量的详细表面物理尚未得到澄清。澄清这一点是今后的一个重要课题。

It is important to clarify the surface alignment of liquid crystal on solid surfaces for physical problem as well as for application to devices, and various researches have been done. However, the surface alignment strength or anchoring energy have not yet been clarified. The research of this grant has focused on this problem and the following results have been obtained.1. A method to measure the surface alignment strength (anchoring energy) has been clarified for substrates whose surface is coated with polymer and rubbed with cloth. 2. Effect of the rubbing strength on the anchoring energy has been investigated by using the newly developed method mentioned above. It was clarified from the results that the anchoring energy was directly depending on the rubbing density. In addition, a reliable and accurate method to control the surface energy was established. 3. Effect of surface anchoring energy, which was controlled by the above mentioned method, on molecular alignment of ferroelectric liquid crystal is investigated. From the results, it was succeeded to form the ideal uniform alignment (bookshelf structure) of the ferroelectric liquid crystal by decreasing the anchoring energy lower than a critical value, which enables to realize electro-optical devices with fast response of microsecond order and excellent memory characteristics. 4. Detailed surface physics which dominate the anchoring energy has not yet been clarified. Clarification of this point is an important future subject.