聚硅氧烷侧链液晶研究进展

阐述了近年来国内外聚硅氧烷侧链液晶的研究进展,介绍了含有两种介晶基元的聚硅氧烷侧链液晶、梯形聚硅氧烷侧链液晶、聚硅氧烷侧链液晶离聚物、聚硅氧烷侧链液晶弹性体的合成方法与产品性能,对聚硅氧烷侧链液晶的应用及研究方向进行了展望。     

液晶聚硅氧烷／硅油稀流体电流变效应的研究

利用Williamson醚合成方法制备了烯丙氧(对乙氧基)联苯，并以其为单体采用催化加聚合成了侧链型联苯聚硅氧烷，并对其结构进行了表征，证实该物质具有液晶性．研究了液晶聚硅氧烷／硅油稀流体的电流变效应，研究发现：该流体具有液晶型电流变液剪切变稀的现象；由剪切应力与剪切速率的关系可以看出，在2kV／mm电场作用下随着剪切速率的增大，产生的剪切应力越大；随着侧链液晶聚硅氧烷／硅油流体重量比的增大，在2kV／mm电场的作用下该流体的剪切应力也增大。     

聚硅氧烷侧链高分子液晶的合成

合成了烯丙氧基苯甲酸对甲氧基苯酚酯（ＡＢＰＭ）和烯丙基胆甾醚（ＡＣＥ），用ＮＭＲ及ＭＳ对其结构进行了鉴定。通过上述两种化合物的末端双键与含氢硅油的Ｓｉ－Ｈ进行催化加成反应，得到了含侧链的聚硅氧烷，红外光谱证明，大部分Ｓｉ－Ｈ已参加了反应。聚合物具有液晶性，聚物和共聚物的液晶相具有不同的特点，分属于向列型，近晶型和胆甾型。     

胆固醇改性聚硅氧烷的合成和血液相容性

合成了胆固醇基团直接键合和通过长链烷基柔性链键合的胆固醇-聚硅氧烷接枝共聚物,研究了胆固醇改性聚硅氧烷的血液相容性.结果表明,未经长链烷基键合的共聚物不能形成液晶相,而经长链烷基键合的共聚物可以形成热致液晶.侧链液晶聚硅氧烷的液晶结构和材料的血液相容性具有独特的依赖性,热处理后形成的液晶相有助于提高材料的血液相容性.     

侧链液晶聚乙炔的合成及性能表征

取向液晶侧链引入聚乙炔主链促使主链共轭性提高,导致获得电活性和取向性的永久结合。最近,已有不少研究组将聚炔共轭聚合物作为刚性主链应用于制备侧链液晶聚合物。文中主要阐述带有液晶侧链聚乙炔的合成、液晶性及光学性能,并根据侧链液晶基元结构对其进行分类。     

一类新的液晶共聚物的合成

以含液晶基元的单体４－「４－（对正丁氧基－苯甲酰氧基）－苯甲酰氧基」－苯基丙烯酸酯和苯乙烯，通过自由基共聚合反应，首次合成了一旬含液昌本和非液晶单体两种结构的共聚物，聚合物的液晶行为用ＤＳＣ、偏光显微镜和射线衍射进行了表征，发现单体有热致液生；所有的共聚物均为向列型热致液晶高分子和具有较宽的液晶太温度范围，随共聚物中液晶性单体含量增加，共聚物分子量、相转变温度和热分解温度呈规律性变化。     

一种组合型液晶聚酰亚胺性能的研究

以3，5－二氨基苯甲酸－4′－联苯酯和4，4′－二氨基联苯等为共聚单体，制备了一种主，侧链均含联苯液晶基元的组合型液晶聚酰亚胺（PI），DSC，WAXD和热台偏光显微镜分析表明该组合型液晶聚酰亚胺呈现层状近晶相织构。主，侧链液晶基元间的原位复合自增强作用使PI－3薄膜的力学强度提高了107％，模量提高了129％，尺寸稳定性提高了40．6％，共聚和侧链液晶基元的引入改善了PI的成膜加工性能，所形成的组合型液晶PI能溶解于常用极性有机溶剂如NMP，DMAc和DMSO中。     

液晶丙烯酸酯／环氧树脂共聚物的合成与表征

本文以致介晶性单体对氨基邻苯二甲酰亚胺烯丙酯，甲基丙烯酸甲酯，丙烯酸为聚单体，通过自由基聚合反应合成了侧链液晶丙烯酸树脂（ＬＣＡＴ）。并与主链型液晶环氧树脂（ＬＣＥＰ）交联共聚，制得了主链－侧链液晶体共聚物，分析了催化剂对聚合反应的影响。并通过ＩＲ，ＤＳＣ和热台偏光显微镜对共聚物的液晶性能进行了表征，结果表明，共聚物有较宽的液晶相变温区。与ＬＣＡＴ，ＬＣＥＰ相比，共聚物的液晶性能增强，并呈现从点状     

液晶基元直接横挂于主链上的液晶共聚物的合成与研究

以含液晶基元的单体２，５－双（４－甲氧基苯甲酰氧基）苯乙与苯乙烯通过自由基共聚合反应，首次合成了一系列含液晶性和非液晶性两种序列结构的共聚物。采用ＤＳＣ、偏光显微镜和Ｘ衍射方法研究了共聚物的液晶行为，发现单体和共聚物（只有ＣＰ－５和ＣＰ－６）有很好的热致液晶性。随共聚物中介晶单体单元含量的增加，共聚物玻璃化转变温度Ｔ和热分解温度Ｔ呈规律变化。     

手性丙烯酸酯侧链液晶共聚物的正电子湮没寿命谱研究

用正电子湮没寿命谱研究了手性丙烯酸酯侧链液晶共聚物分子主链与介晶基元侧链的运动行为及相互作用。结果表明，侧链液晶基元的取向随磁场强度增加而增加，当磁场强度达到一定值后则趋于恒定。侧链介晶基元受磁场的诱导取向对分子主链运动的影响为非线性效应。     

光刻法制备聚合物/液晶光栅

将明胶涂覆在表面经过取向处理的带有ITO电极的玻璃基板上，以紫外灯为光源，通过光掩模法，使明胶在光场的引发下发生光化学反应，样品显影刻蚀处理后呈栅状，将液晶注入光栅盒中，形成聚合物／液晶光栅。该光栅衍射效率可利用电场调控。采用He—Ne激光器对所制样品进行测试，结果表明，所制样品的栅结构较好。避免了液晶与聚合物相分离的不完全性和栅条边缘不整齐的现象。制得的光栅其第一衍射级次的开关比为87：1，显示了较好的开关能力。     

液晶提纯方法综述

对液晶单体和混合液晶的提纯方法进行了论述和总结.     

Molecular alignment structure of dimeric liquid crystals

While an antiferroelectric liquid crystal (AFLC) with dimeric molecules which take a bent molecular structure may show the phase transition from the isotropic liquid to the chiral smectic-C AFLC () phase via the nematic (N) phase, it has not been obvious yet why the and N phases may coexist in the phase sequence of the dimeric AFLC medium. In this study, the molecular alignment structures of the N and the SmC_A phases of an achiral dimeric LC were researched in detail with a polarized Fourier transform infrared spectroscopy (FT-IR). The domain structure with two orientational directions is formed both in the SmC_A and N phase, and the occupation ratio of two types of domain does not change in the phase transition. Since their alignment structures are basically same except for the existence of layer structure, their phases may coexist in the phase sequence of the dimeric AFLC.     

α，ω－对乙氧羰氧基苯甲酸聚乙二醇酯液晶的合成及转变性能研究

用模型化合物的方法，合成了一系列含柔性间隔链段芳香聚醚酯液晶化合物（ＰＥＥＣＢ－ｎ），通过１ＨＮＭＲ、ＤＳＣ、正交偏光显微镜、ＷＡＸＤ等手段，对其结构和液晶态转变进行了表征。     

含芳酯键的液晶双马来酰亚胺的合成与表征

本文通过对马来酰亚胺基苯甲酸及其酰氯化路线合成了两种含芳酯键的液晶双马来酰亚胺。应用FT-IR、~1H-NMR、DTA、DSC、热台偏光显微镜对双马来酰亚胺的结构、热性能和相转变进行了表征。这类双马来酰亚胺具有较好的热致液晶行为,并且液晶织态结构可以通过端基的交联聚合反应固定在交联网络中。     

Organic semiconductor-based photonic crystals for solar cell arrays: band gap and optical properties

Photonic crystals (PCs) hold great potential for designing new optical devices because of the possibility of the manipulation of light with PCs. There has been an increase in research on tuning the optical properties of PCs to design devices. We design organic semiconductor-based PC structures and calculate optical properties using the plane wave expansion method and finite-difference time-domain method in an air background for a hexagonal lattice. We showed the possibility of the solar cell arrays for a 2D PC cavity on an organic semiconductor base infiltrated with a nematic liquid crystal. E7 type has been used as a nematic liquid crystal and 4,4′-Bis[4-(diphenylamino) styryl]biphenyl as an organic semiconductor material.     

Morphological control and polarization switching in polymer dispersed liquid crystal materials and devices

Liquid crystals dispersed in polymer systems constitute novel class of optical materials. The precise control of the liquid crystal droplet morphology in the polymer matrix is essentially required to meet the prerequisites of display device. Experiments have been carried out to investigate and identify the material properties and processing conditions required for the precise control of the droplet morphology of the dispersed liquid crystal systems. Polarization switching has been studied. Aligned liquid crystal dispersed systems showed higher polarization over unaligned ones.     

液晶显示技术综述

传统的显示器应用阴极射线管CRT，需要高电压，体积大，能耗高，而且反射短波射线，对人体有伤害，液晶显示器与之相比，有其突出的优越性，低能耗，轻，对人体无损害，因此已规模生产并推广应用，本文系统阐述了液晶显示技术的基本原理，发展历程以及我国液晶显示器产业的现状和发展前景。     

Photoaligned Nanorod Enhancement Films with Polarized Emission for Liquid‐Crystal‐Display Applications

Semiconductor nanorods (NR) emit polarized light, which is expected to bring manifold benefits, in terms of brightness and color enhancement, for modern liquid‐crystal displays (LCD). In this regard, photoaligned nanorod enhancement films (NREF) for color and polarization conversion for LCD backlights are introduced here. The photoinduced anchoring forces, by the photoalignment layer, stimulate well‐ordered self‐assembly of NR in the thin polymer films. Green and red emitting NR with a quantum yield of ≈80% are aligned unidirectionally and in‐plane, showing a polarization ratio of >7:1 and a degree of polarization of >0.81. The photoalignment technique facilitates the fabrication of mixed and multiple stacked NREF for LCDs, which improves the color gamut and polarization efficiency, and is thus expected to increase the optical efficiency of conventional LCDs by ≈60%.