热致型光敏液晶高分子在液晶场中光交联反应的研究

研究了具有肉桂酸酯侧链基的热致型液晶高分子的光交联行为．结果表明，在２０ｍｉｎ紫外光照射的条件下，形成液晶相的液晶高分子膜的光交联凝胶百分率要明显高于尚未形成液晶相的同种高分子膜．对形成液晶相的高分子膜，在环境温度低于液晶各向同性温度Ｔ时，温度对光交联凝胶百分率的影响甚微．这表明，由于液晶高分子中致介单元的聚集和有序排列形成的微区结构也影响了大分子链侧基肉桂酸酯的聚集状态．从而使其光化学性质发生变化．     

端基含36个己氧基偶氮苯基元的二代碳硅烷光致变色液晶树状高分子的光化学研究

研究了含36个己氧基偶氮苯介晶基元的二代(G2)光致变色液晶树枝状高分子在氯仿和四氢呋喃溶液中的最大吸收波长,摩尔消光系数,反顺光异构化反应速率常数,光化学回复异构化正逆反应速率常数及其平衡常数,G2和G1的光致变色反应速率常数kp为10-1s-1,而含偶氮基元光致变色液晶聚硅氧烷的kp为10-8s-1,因此液晶树状高分子的光响应速率比后者快107倍.     

侧基甲壳效应和甲壳型液晶高分子

侧链液晶高分子体系里,液晶基元可以通过尾接或腰接的方式与主链相连.一般认为,在液晶基元与主链间插入一段长度合适的＂柔性间隔基＂可有效实现主、侧链间的动力学去偶合,从而有利于侧基液晶基元之间的有序排列.作为一类特殊的腰接型侧链液晶高分子,甲壳型液晶高分子中体积较大的侧基（如棒状液晶基元）通过非常短的间隔基或仅通过一个碳-碳键直接横挂至主链上,这导致了强烈的甲壳效应,使得主链被迫伸展.因此,可从与＂柔性间隔基＂完全不同的角度出发,充分利用主链和侧基间的偶合作用,设计甲壳型液晶高分子.本文综述了腰接型侧链液晶高分子中的侧基甲壳效应、甲壳型液晶高分子中由主链与侧基相互作用所导致的特殊构象以及液晶相结构.研究表明,侧基甲壳效应在调控甲壳型液晶高分子的形状、尺寸以及螺旋结构等方面有重要作用.甲壳型液晶高分子可作为刚-柔嵌段共聚物的刚性链段,也可作为主/侧链结合型液晶高分子的主链部分参与到多层次分级超分子有序结构的构筑之中.     

聚苯撑苯并二噻唑的甲基磺酸溶液的相转变过程及其动力学研究

 用退偏振光强度法及偏光显微镜研究了溶致性液晶高分子聚苯撑苯并二噻唑的甲基磺酸溶液(PBT/MSA)由液晶相至各向同性相(N→I转变),及由各向同性相至液晶相(I→N转变)的相变过程.液晶相的形成(I→N)服从Av-rami方程,Avrami指数为1左右,表明该体系的液晶相是以一维棒状方式形成的.相转变温度与浓度有关,提高温度可加速在应力下液晶相长程有序结构的形成.     

发光液晶高分子:分子构筑、结构与性能及其应用

发光液晶高分子结合了液晶高分子的有序性、稳定性、力学性能和发光分子的发光特性,有着广阔的应用前景。为了获得高效的发光液晶高分子,不同结构的发光液晶高分子被成功地设计与合成,包括主链型、侧链型、“甲壳”型发光液晶高分子、发光液晶高分子网络等。同时,分子结构、液晶相结构与光物理性质的关系也得到了相应的深入研究。本文总结了发光液晶高分子的最新研究进展,详细介绍了不同类型发光液晶高分子的分子结构设计合成、结构与性能、相关应用,并对其发展前景进行了展望。     

刚柔相嵌液晶高分子的赝二级相变温度

讨论了刚柔相嵌液晶高分子的向列相一各向同性相转变与其分子结构的关系．给出了该一级相变的赝二级相变温度Ｔ＊与这类液晶高分子的液晶基元和间隔基的长度、柔顺性（相关长度）以及它们之间的相互作用的关系的解析表示式．分析了液晶基元与间隔基连接处的表观弯曲（接口效应）对Ｔ＊的影响．文中的结论与实验相符．     

树状高分子的功能化进展

介绍了近年来高分子化学领域中十分活跃的树状高分子的研究状况,对目前树状高分子的最新功能化进展进行了评述,着重介绍了具有光活性、电活性、生物活性的树状高分子,以及树状高分子与富勒烯的衍生物。     

树状高分子的特性粘数与代数的关系

从爱因斯坦的粘度理论出发 ,联系树状高分子的分子结构参数 ,计算了树状高分子的特性粘数 ,得到了树状高分子的特性粘数与代数的内在关系 ,分析了树状高分子特性粘数特异行为的内在原因 ,使得对树状高分子特性粘数的理论预测成为可能     

《功能高分子材料》

全书共分17章，结合功能高分子材料的结构与性能、制备方法及应用领域，对离子交换树脂，吸附树脂，离子交换纤维和活性碳纤维，高分子膜分离材料，高分子色谱固定相，高分子试剂，高分子负载催化剂，导电高分子材料，电效发光聚合物材料，非线性光学高分子材料，液晶高分子材料，感光高分子材料，医用高分子材料，环境敏感高分子材料，高分子电解质，高分子染料，淀粉，纤维素衍生物高分子等进行了详细论述。[第一段]     

含X-型和棒型两种液晶基元的主链型系列芳族共聚酯的研究

 采用含X-型和棒型液晶基元的两种不同单体,通过改变X-型液晶基元单体的结构和柔性链段长度,经高温溶液缩聚,合成了一系列主链型共聚液晶高分子.研究发现,所有样品都具有很好的热致液晶性及宽广的液晶态温度范围.随单体结构改变,共聚物的相转变温度大致呈规律性变化.     

Highly congested liquid crystal structures: dendrimers, dendrons, dendronized and hyperbranched polymers

In this tutorial review we describe some studies concerning liquid crystal dendritic polymers. We have chosen to present several representative examples that illustrate the diverse kinds of LC dendritic structures, namely: dendrimers, dendrons, dendronized polymers and hyperbranched polymers. We review their synthesis, mesogenic properties and the way that they are arranged to form supramolecular liquid crystal assemblies.     

Structures and properties of dendrimers having peripheral 2,3-difluorobiphenyl mesogenic units: effects of dendrimer generation

1st-5th generation poly(propyleneimine) dendrimers having peripheral 2,3-difluorobiphenyl mesogenic groups have been synthesized. They exhibited smectic liquid crystalline behaviour. All the liquid crystalline dendrimers exhibited a smectic A (SmA) phase and a crystal E (E) phase. The SmA-isotropic phase transition temperature increased with increasing generation. In addition, a homeotropic structure was spontaneously formed on a glass plate in the SmA phase for the 2nd, 3rd, and 4th generation dendrimers. The hometropic structure remained unchanged in the phase.     

Synthesis and structure of wholly aromatic liquid–crystalline polyesters containing meta- and ortholinkages

Wholly aromatic main-chain rigid-chain polymers containing meta- and orthokink linkages were synthesized. The thermal property, liquid crystallinity, and crystalline structure were studied using DSC, polarized light microscopy, and wide-angle X-ray scattering. These polymers exhibited liquid crystallinity up to 50 mol % of meta- and orthokink linkages. The existence of liquid crystallinity in these polymers may be attributed to the adoption of cis conformation in kink units in these polymers because the energy penalty for doing so can be compensated by the formation of the liquid–crystalline phase. The crystallinity of the polymers was low, and the crystal structure was quite similar to that of the pure polymers (without kink units). This can be explained by that fact that the crystal region mainly consists of the nonkink units, and the kink units disrupt the crystallization of the polymers and form defects. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1242–1248, 2001     

A Small Change in Central Linker Has a Profound Effect in Inducing Columnar Phases of Triazine‐Based Unconventional Dendrimers

Four unconventional triazine‐based dendrimers have been prepared and characterized by ¹H and ¹³C NMR spectroscopies, mass spectrometry, and elemental analysis. Based on DSC studies, polarizing microscopy, and powder XRD, two of these dendrimers, containing linkers with an odd number of carbon atoms, were observed to display columnar liquid–crystalline phases during thermal treatment. However, the other two dendritic analogues, containing linkers with an even number of carbon atoms, were not observed to behave correspondingly. Based on computer simulation, we reasonably assume that the dendrimers with an odd number of carbon atoms in their linkers distort their molecular shape and adopt two isomeric structures due to asymmetrical congestion. This reduces the molecular π–π face‐to‐face interaction, which in turn causes the dendrimers to form columnar LC phases during thermal treatment. However, the dendrimers with an even number of carbon atoms in their linkers have more symmetrical skeletons and do not display any liquid–crystalline phase upon thermal treatment. This new strategy should be applicable for eliciting the columnar liquid–crystalline properties of other types of unconventional dendrimers with rigid frameworks.     

Interaction of cellulose with other polymers: retrospective and prospective

Interaction of cellulose with other polymers is reviewed from retrospective viewpoints, and future opportunities are discussed from prospective scopes. Previous investigations of the interaction of cellulose with other polymers and/or its existence in novel conformations include a brief overview of cellulose crosslinking, grafting, cellulose/other polymer microcomposites and cellulose and its derivatives in the liquid crystalline state. Interaction of cellulose with newer and more novel macromolecular architectures include its ability to form and interact with polyrotoxanes, polymer combs, starburst dendrimers and hyperbranched polymers and its use as an intelligent material. © 1998 John Wiley & Sons, Ltd.     

Scattering from polymer films and its application to optical properties of blends and display devices

The application of the technique of observing the light scattering from solid polymers for the study of amorphous phase separation, spherulitic crystallization, phase separation in crystalline polymers, and coarsening of liquid crystal polymers is reviewed. The effect of shear and electrical and magnetic fields on liquid crystal orientation is discussed and its application for constructing light control and display devices is considered.     

SYNTHESIS AND PROPERTIES OF NEW MESOGEN-JACKETED LIQUID CRYSTALLINE POLYMERS*

Some new mesogen-jacketed liquid crystalline polymers (MJLCP) with polymer backbones, spacers, andmesogenic units of different structures were synthesized by radical polymerization. The mesomorphic behavior of thesepolymers was examined using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Theirliquid crystallinity is influenced by the variation of polymer backbone, spacer, mesogenic unit and its terminal groups. Theresults show that 1) a more flexible polymer main-chain is more favorable to the formation of a liquid crystal phase, while 2)a flexible spacer will decrease the "Jacket Effect" and the liquid crystallinity and 3) a subtle modification of the terminalgroups on the mesogenic unit may also have a significant influence on properties of the polymers.     

液晶金属配位聚合物的合成及性能

基于国内外最新研究文献 ,系统论述了近年来液晶金属配位聚合物的合成方法、液晶行为及应用前景。指出液晶金属配位聚合物的合成方法可归纳为直接配位法、单体配位法、交联配位法和聚合物反应法四种。液晶金属配位聚合物一般呈现热致液晶行为 ,显示稳定的向列液晶相或近晶液晶相。有些金属配位聚合物还呈现互变性近晶态或单变液晶性。液晶金属配位聚合物具有金属的特殊性质 ,是一种新型高性能磁导、电导和光导材料 ,可望应用于液晶显示材料、磁性信息储存薄膜材料、润滑剂和各向异性催化剂等。     

手性聚甲基丙烯酸酯液晶聚合物的合成及相行为的研究

手性聚甲基丙烯酸酯液晶聚合物的合成及相行为的研究向前，张纪宇，张树范（中国科学院化学研究所北京１０００８０）关键词手性液晶聚合物，相行为手性侧链液晶聚合物在侧链中含有不对称碳原子的末端基，使聚合物显示Ｓｔ相．Ｓ？相层中的分子呈倾斜排列而产生自发极化．...