Coating Films of Liquid Crystalline polymers as Alignment Layrs

我们尝试用一种液晶聚合物涂层来开发一种新的取向层。采用各向同性和液晶状态的水溶液和乙醇溶液作为涂层材料。本文的研究结果如下：1。随着涂层速度的增加和膜厚的减小，单位长度上的棱纹数量增加。在高镀膜速度下，在液晶溶液中制备的薄膜中观察到带状织构。在各向同性溶液制备的涂膜上，当涂膜较薄且涂膜速度较高时，将5CB液滴置于涂膜上，发现了液晶分子在涂膜上沿一个方向排列的偏斜线。相反，在低镀膜速度下加工的厚膜的取向状态是随机的。用原子力显微镜（AFM）观察了涂层的表面形貌。发现了与带状结构相对应的微肋。在其他膜中均未发现引起5CB分子取向的结构。在Doi模型对液晶聚合物自旋流动的数值模拟中，由于拉长流动，分子在靠近细丝表面的区域与流动方向平行排列。我们得出结论，各向同性溶液处理的膜上的5CB分子取向是由固定在膜表面附近的HPC分子的流动诱导取向引起的。

We tried to develop a new alignment layr by using a coating film of luquid crystalline polymers. Aqueous solutions and ethanol solutions both in isotropic and liquid crystalline states were used as coating materials. Results obtained in the present work are as follows.1. The ribbing phenomenon was occurred and its number per unit length increased with increasing velocity of coating and decreasing film thickness.2. The band texture was observed in the thin films processed from the liquid crystalline solutions at high coating velocities.3. The disclination line, which indicates that the molecules of liquid crystals align in a one direction on a coating film, was found in a droplet of 5CB placed on the coating film processed from isotropic solutions if the film is thin and the coating velocity is high. On the contrary, it was confirmed that the alignment state was random for thick films processed at low coating velocities.4. The surface morphology of coating films was measured with an atomic force microscope (AFM). The micro ribs, which corresponded to the band texture, was found. Any structures, which induced the molecular alignment of 5CB,were not able to be specified in the other films.5. In the numerical simulation of spinning flow of liquid crystalline polymers using the Doi model, molecules align parallel to the flow direction in the region close to the filament surface because of the elongational flow.6. We concluded that the molecular alignment of 5CB on the films processed from the isotropic solutions was caused by the flow-induced alignment of HPC molecules fixed only in the vicinity of the film surface.