液晶显示用取向材料聚甲基丙烯酸肉柱酰氧基乙酯的光控取向研究

通过实验研究了光聚合物材料聚甲基丙烯酸肉柱酰氧基乙酯（ＣＥＭＣ）的光化学反应过程,以及对液晶材料ＬＣ－６７０１Ａ的取向能力。通过原子力显微镜（ＡＦＭ）观察了取向层表面在光化学反应前后的变化,测量了光控了以向膜液晶盒中液晶分子的预倾角及单面光控取向扭曲现列液晶显示器（ＴＮＬＣＤ）的电光特性和时间响应特性曲线,研究了液晶分子排列取向的机理。     

LB膜技术在液晶取向中的应用

本文以ＬＢ膜技术研究了向列相液晶的取向机理。选择了四种不同金属的可溶性酞菁化合物ＭＰｃ－Ｒ４作为取向材料，拉制成ＬＢ膜，诱导向列相正性液晶Ｅ－７。通过对菁酞ＬＢ膜的表征和液晶取向及电光性能的研究，认为液晶的取向是由分子间的相互作用力决定的。     

C60不同吸附取向的STM图象的理论模拟

采用离散变分局域密度泛涵（ Ｄ Ｖ Ｌ Ｄ Ｆ） 方法,基于 Ｔｅｒｓｏｆｆ Ｈａｍａｎｎ 的扫描隧道显微镜（ Ｓ Ｔ Ｍ） 理论,通过计算单个 Ｃ６０ 五种不同吸附取向的电荷密度分布图来模拟其 Ｓ Ｔ Ｍ 图象．计算结果表明,不同取向 Ｃ６０ 的电荷密度分布图有各自的特征‘指纹’,其中模拟正偏压情形下 Ｃ６０ 的最低未占据分子轨道（ Ｌ Ｕ Ｍ Ｏ） 分布图与其 Ｓ Ｔ Ｍ 图象具有较好的可比性．与实验上已有的 Ｓ Ｔ Ｍ 图象和文献中的理论计算结果比较,可以确定 Ｃ６０ 在一些表面上的吸附取向．根据我们实验上获得的 Ｓ Ｔ Ｍ 图象及理论模拟结果,发现 Ｃ６０ 在 Ｓｉ（１１１）７ ×７ 表面存在一种新的吸附取向,即５ —６ 键朝上．计算结果还对 Ｓ Ｔ Ｍ 的实验工作具有一定的指导意义,并可以采用这一方法,用来确定其他分子的吸附取向．     

M3C60（M=K,Rb）中C60分子的取向机制研究

研究Ｍ３Ｃ６０（Ｍ＝Ｋ，Ｒｂ）中Ｃ６０分子的取向机制，利用点电荷模型和Ｌｅｎｎａｒｄ－Ｊｏｎｅｓ势考察了Ｋ＾＋－Ｃ６０和Ｃ６０－Ｃ６０之间的相互作用对Ｃ６０分子取向的影响。结果表明：Ｍ＾＋－Ｃ６０之间的相互作用对Ｃ６０分子的取向起决定作用，而使得Ｃ６０分子的基态取向为两个标准取向之一。     

利用核磁共振氢谱的哈勒分析获得分子序列取向参数

本文通过全氢液晶材料的核磁共振氢谱（¹H NMR）的哈勒关联研究推测了分子序列取向参数,包括随温度变化的双峰距离及全谱图的半高峰宽.通过哈勒拟合并外推所得到的4'-正戊基-4'-氰基联苯（5CB）和混合液晶E7分子取向参数,与其它方法获得的取值一致.     

聚甲基丙烯酸肉桂酰氧基乙酯的光化学反应在液晶分子排列取向中的作用

研究了光聚合物材料聚甲基丙烯酸肉桂酰氧基乙酯(CEMC)对液晶材料LC-6710A的取向作用,取向层表面在光化学反应前后的变化;测量了光控取向膜液晶盒中液晶分子的预倾角及单面光控取向扭曲向列液晶显示器(TNLCD)的电光特性和时间响应特性,研究了这种材料的光化学反应过程,以及液晶分子排列取向的机理.     

用于液晶取向的掺偶氮类染料的光诱导取向膜

介绍了一种使用聚酰亚胺和偶氮类染料进行液晶光诱导取向技术,深入研究了代号为SY04包含两个偶氮基团的新偶氮类染料.通过对取向膜偏振吸收光谱的分析,讨论了这种混合材料光诱导取向机理.由于聚酰亚胺良好的成膜性使得这种光诱导取向膜具有很好的稳定性,偶氮类染料的引入使得液晶表面取向更加有序,从而获得了响应快速,电光特性优良的液晶盒.这种取向膜材料同时具有很好的热稳定性及抗紫外稳定性.     

红外透过、反射吸收光谱研究手性液晶(M1)LB膜的结构与取向

利用ＦＴＩＲ光谱研究了一种手性液晶化合物（Ｍ１）ＬＢ膜的结构与取向,该化合物可以形成稳定的单层与多层膜。手性分子中,芳香环平面向于垂直基片表面,分子中的烷基链部分则与基底表面法线方向成一定的角度。     

取向Kerr效应对液晶光控取向质量的影响

取向Ｋｅｒｒ效应对液晶光控取向质量的影响＊王淑梅ａ）梁兆颜闫石谢景力ｂ）田颜清ｂ）黄锡民ａ）（中国科学院激发态物理开放研究实验室，长春１３００２１）（中国科学院长春物理研究所，长春１３００２１）ｂ）（吉林大学化学系，长春１３００２３）关键词取向Ｋｅｒ...     

非晶PET纤维的分子链段取向分布的研究

用对称透射法,收集在室温下不同拉伸比的非晶聚酯（ＰＥＴ）纤维之二有Ｘ射线散射（ＷＡＸＳ）强度函数Ｉ（κ,α）,采用自编ＭＰＳ９６型全谱分峰程序,将不同方位角α测得的ＷＡＸＳ强度曲线上的４个非晶重叠峰进行分解,获得分子链间原子 射引起的２个峰为：ＫＡ＝０．１４１ｎｍ＾－１,ＫＢ＝０．１７２ｎｍ＾－１;分子链内原子 射引起的２个峰为;ＫＣ＝０．３１１ｎｍ＾－１,ＫＤ＝０．５５５ｎｍ＾－１,详细分析了     

A NEW METHOD TO ALIGN LIQUID CRYSTAL MOLECULES BY LINEAR PHOTO-POLYMERIZATION FOR LIQUID CRYSTAL DISPLAY

A new technique to uniformly align liquid crystal molecules is presented. The technique is based on producing an anisotropic surface on the glass substrate coated with photo-polymers by photo-polymerization of linear polarized UV-light. The orientation of liquid crystal molecules is governed by the direction of the polarized vector of UV-light. Using this method, we have studied the photo-polymer PSi-CM aligning LC 6710A molecules. The liquid crystal microscopic texture between crossed polarizers, optical retardation from liquid crystal layers and electro-optical properties of twisted nematic liquid crystal display cell are obtained, which was prepared with one side -photo-alignment and the other side-rebbed substrate.     

表面垂直取向对HPDLC光栅特性的影响

为了提高聚合物/液晶（HPDLC）光栅的衍射效率并改善光栅的表面形貌,研究了表面垂直取向处理对HPDLC光栅的影响。首先,研究了表面垂直处理对液晶分子的取向作用,发现垂直取向层对液晶的锚定作用随着盒厚的增加而逐渐减弱,取向层的作用范围大概在3 m ~5 m之间;其次,对相分离程度进行了实验表征,结果表明,随着液晶盒厚度的增加,相分离开始的时间越来越快,并且分离程度也越来越彻底。最后,讨论了表面垂直取向对HPDLC光栅衍射效率的影响,随着盒厚的增加,相分离出来的液晶微滴形成连续的区域,光栅的衍射效率逐渐升高,当盒厚增加到一定程度,其衍射效率和无取向处理的光栅接近。当盒厚过大时,垂直取向处理对HPDLC光栅散射损失并没有太大的改善,只有当盒厚适中（12 m）时,光栅的衍射效率最高,散射损失最小。     

Dynamic operation of liquid crystal cell with inherently nanogroove-featured aligned carbon nanotube sheets

The use of a highly aligned carbon nanotube (CNT) sheet as a multifunctional constituent for liquid crystal (LC) displays and electro-optic LC applications is assessed. The CNT sheet can perform a dual function: one is an alignment layer for LCs, replacing the commonly used rubbed polyimide film, and the other is a transparent conductive layer, taking the place of indium tin oxide. The hydrophobic treatment improved the adhesion quality between aligned CNT bundles and the glass substrate, which helps to preserve the inherently aligned nanogroove morphology of transparent CNT sheets. The test LC display cells, comprising 4-cyano-4′-pentylbiphenyl molecules sandwiched between CNT-sheet-on-glass substrates, demonstrate the operation characteristics comparable to that of the conventional cell under temperature variation and ac electric field of 1?kHz. The results offer a possibility of deploying multifunctional CNT-sheet alignment layers in LC-based devices, especially in the future flexible display applications.     

Increasing the rewriting speed of optical rewritable e-paper by selecting proper liquid crystals

The effect of interaction between liquid crystal(LC) and photoalignment material on the speed of optical rewriting process is investigated.The theoretical analysis shows that a smaller frank elastic constant K 22 of liquid crystal corresponds to a larger twist angle,which gives rise to a larger rewriting speed.Six different LC cells with the same boundary conditions(one substrate is covered with rubbed polyimide(PI) and the other with photo sensitive rewritable sulfuric dye 1(SD1)) are tested experimentally under the same illumination intensity(450 nm,80 mW/cm 2).The results demonstrate that with a suitable liquid crystal,the LC optical rewriting speed for e-paper application can be obviously improved.For two well known LC materials E7(K22 is larger) and 5CB(K22 is smaller),they require 11 s and 6 s corresponding to change alignment direction for generating image information.     

What aligns liquid crystals on solid substrates? The role of surface roughness anisotropy

The mechanism responsible for liquid crystal (LC) alignment on mechanically buffed or UV exposed polymer films is poorly understood. A comprehensive study of LC alignment on variously prepared substrates unequivocally shows that the anisotropy in the surface roughness of the substrate completely determines the direction of LC alignment. In all the cases studied, including those where an anchoring transition occurs with temperature, the LC director (re)aligns in the directions of low roughness.     

向列相液晶沿面到垂面排列转变的分子场理论

以摩擦基板间的液晶薄层为研究对象,用分子场理论研究了向列相液晶分子排列转变行为.分子质心固定在简单立方晶格的格点上.液晶由极性分子构成,与基板相接触的一层分子同时受到色散和极性两类表面作用.通过自洽的数值计算,获得3种相图,清楚地展示了摩擦基板间向列相出现的从高温沿面到低温垂面排列的转变;获得实现这类转变所需要的两类表面作用的参数范围.结果表明:基板的摩擦会改变基板表面色散作用,但不会影响基板表面极性作用;表面极性相互作用能引起基板间向列相液晶发生沿面到垂面排列转变.     

Liquid crystal orientation transition on microtextured substrates

A uniform alignment of liquid crystal (LC) with finite pretilt was observed on microtextured substrates that were lithographically fabricated with alternating horizontal and vertical corrugations. As the period of alternation was decreased toward 0.8 microm, the nematic LC alignment on these substrates changed from inhomogeneous in plane, copying the substrate corrugations, to a uniform configuration with a large pretilt of approximately 40 degrees. This transition is pertinent to a frustrated boundary wherein a lowering in the LC elastic energy due to spatial variation in the LC orientation compromises an increase in the surface anchoring energy. A model based on this idea demonstrates good agreement with the experiment. This result may open up a new arena for tailoring substrate characteristics for LC alignment.     

Electro-optical switching of liquid crystal diffraction gratings by using surface relief effect in the photopolymer

Surface relief patterns are one of the promising possibilities for the fabrication of liquid crystal (LC) electro-optical devices. Optically recorded surface relief gratings in an acrylamide based photopolymer were filled with the liquid crystal to fabricate liquid crystal diffraction gratings. E49 liquid crystals were used in this work. The switching behaviour of the diffraction grating was investigated by measuring the intensity in the first order when an electric field was applied.     

Increasing rewriting speed of optical rewritable e-paper by selecting proper liquid crystals

Effect of interaction between liquid crystal (LC) and photoalignment material on speed of optical rewriting process is investigated. The theoretical analysis shows that smaller frank elastic constant K₂₂ of liquid crystal corresponds to larger twist angle, which gives rise to larger rewriting speed. Six different LC cells with the same boundary conditions (one substrate is covered with rubbed polyimide (PI) and other with photo sensitive rewritable sulfuric dye 1(SD1)) are tested experimentally under the same illumination intensity (450 nm, 80 mW/cm²). The results demonstrate that with suitable liquid crystal, LC optical rewriting speed for e-paper application can be obviously improved. For two well known LC materials E7 (K₂₂ is larger) and 5CB (K₂₂ is smaller), they require 11 s and 6 s corresponding to change alignment direction for generating image information.