Novel Method to Control Liquid Crystal Orientation based on Water Flow-induced Molecular Alignment

基于水流诱导分子排列控制液晶取向的新方法

基本信息

批准号：
12555267
负责人：
KIKUCHI Hirotsugu
金额：
$ 2.82万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

The uniform alignment of liquid crystal (LC) molecules is generally produced by a surface-induced alignment technique of a polymer surface. However, the conventional rubbing technique involves a serious problem that an electrostatic charge and dust are generated during mechanical friction by rubbing. In this study, a novel liquid crystal alignment technique was investigated in order to realize electrostatic charge-and dust-free on the polyimide surface. A uniform alignment of LC was obtained by using the polyimide surface which was exposed to unidirectionally flowing water at 343 K before imidization by thermal cure.The surface-induced alignment effect was not sufficient in the case of exposing the polyimide surface to the water flow after the thermal imidization. The local chain orientation on the polyimide precursor surface induced by exposing to the water flow and its amplification of the chain orientation by the thermal imidization is a possible mechanism of "water flow rubbing".Interface enhanced sum-frequency generation (ISFG) method is a second-order nonlinear optical technique, which is a powerful tool to study the surface and the interface. The ISEG method was used for investigating 4-cyano-4'-pentylbiphenyl (5CB) behavior at the (polymer / 5CB) interface. Poly (vinyl cinnamate) and poly (vinyl alcohol) were used as polymer. In both ISEG spectra, the absorbance bands attributed to the CN-stretching bands of 5CB were observed. At the (PVCi /5GB) interface, the absorbance band of CN-stretching appeared at 2225 cm^<-1>, which was in good agreement with CN-stretching band in the ET-IR spectrum of 5CB in the bulk state. However, at the (PVA/ 5CB) interface, the band of CN-stretching was sifted 100 cm^<-1> to lower frequency. This results indicate that the intermolecular interaction between PVA and 5CB is much larger than the case of PVCi and 5GB.

液晶（LC）分子的均匀比对通常是由聚合物表面表面诱导的比对技术产生的。但是，常规的摩擦技术涉及一个严重的问题，即通过摩擦在机械摩擦过程中产生静电电荷和灰尘。在这项研究中，研究了一种新型的液晶比对技术，以实现在聚酰亚胺表面上无静电电荷和无尘。通过使用聚酰亚胺表面获得LC的均匀比对，该表面在343 K处暴露于单向流动的水之前，然后通过热疗法添加添加。在热浸泡后，表面诱导的比对效应不足以使聚酰亚胺表面暴露于水流中。通过暴露于水流量及其通过热imidation对链取向诱导的聚酰亚胺前体表面上的局部链取向是“水流摩擦”的可能机制。接口增强的增强型总频率产生（ISFG）方法是二阶非线性光学技术，是一种强大的工具，是一种强大的工具，是一种研究表面和互面的工具。 ISEG方法用于研究（聚合物 / 5CB）界面处的4-氰基-4'-苯基苯基（5CB）行为。聚（乙烯基肉桂酸）和聚乙烯醇作为聚合物。在两个ISEG光谱中，都观察到归因于5CB的CN伸展带的吸光度带。在（PVCI /5GB）界面上，Cn伸展的吸光频带的吸光度为2225 cm^<-1>，它与散装状态的5CB的ET-IR光谱中的CN伸展带非常吻合。但是，在（PVA/ 5CB）界面上，将CN拉伸的频带筛选为100 cm^<-1>至较低的频率。结果表明，PVA和5CB之间的分子间相互作用比PVCI和5GB的情况大得多。