ORGANOMETALLIC FERROELECTRIC LIQUID CRYSTALS Ⅰ. LIQUID CRYSTAL PROPERTIES OF ORTHO—PALLADATED BINUCLEAR COMPLEXES OF AZINE, IMINE AND AZO DERIVATIVES

The mesomorphie properties of title complexes are investigated by means of DSC and polarizing microscopy. The mesophase temperature ranges of complexes are wider than that of corresponding organic ligands. The bridging groups of the complexes have profoand effects on the mesomorphic behavior, When the bridging groups are opticallhy active. the compleve show chiral smectic

SYNTHESIS AND MESOGENIC PROPERTY OF Pd-COORDINATING AZO-TYPE SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANE

A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium dichloride and potassium chloride in the presence of tetrahydrofuran （THF） as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T;is increased and the mesophase range ΔT has been widened, too.

STUDY ON MAGNETIC FIELD-INDUCED 0RIENTATI0N OF A CHIRAL SIDE-CHAIN LIQUID CRYSTAL POLYACRYLATE USING INFRARED DICHROISM

Magnetic field-induced orientation of a chiral side chain liquid crystalline polyacrylate(P-11) was studied by using IR dichroism. For the investigated P-11, it has been shown thatthe magnetic alignment takes place over the entire temperature range between its meltingpoint and clearing point and the orientation level is strongly temperature-dependent, thedevelopment with time of the magnetic orieatation follows an exponeotial-type relation,and the smectic phase state influences the thermal relaxation process in the absence of themagnetic field.

SYNTHESIS AND CHARACTERIZATION OF PALLADIUM COORDINATING IMINE SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANES

New thermotropic chloro-bridged dinuclear palladium coordinating imine side chain liquid crystalline polysiloxanes have been synthesized. Their mesomorphic properties have been investigated by DSC, X-ray diffraction and polarizing microscopy. The polymeric complexes show nematicdiscotic (Nd) mesophase. It is found that the temperature range of liquid crystalline state of chloro- bridged polymeric complexes is much wider than that of acetato- bridged ones and imine side chain polysiloxane. This indicates that the disc-like chloro-bridged palladium complexing units play a role as mesogen in mesophase.

SYNTHESIS AND PHASE BEHAVIOUR OF CHIRAL COMBINED MAIN/SIDE CHAIN LIQUID CRYSTALLINE COPOLYMERS

The synthesis and phase behaviour of chiral combined main/side chain liquid crystallinecopolymers containing pendant group constituted by chiral side group and trans-azobenzenemoiety with nitro end group are described. The formation of liquid crystalline polymorphism ofcopolymers is influenced by various contents of achiral side group.

SYNTHESIS OF A GROUP OF MESOGEN JACKETED LIQUID CRYSTAL POLYMERS

A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the primary characterization of the liquid crystal phase of the monomers and the polymers are described. While some of the monomers give smectic textures the polymers are found to be nematic above their melting or glass transition temperatures. Interestingly the unsubstituted monomer and its polymer poly 2,5-di( benzoyloxy ) styrene are also liquid crystalline. The single crystal structure of one of the monomers is also discussed.

SYNTHESIS AND CHARACTERIZATION OF β-DIKETONE BASED SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANES

A new type of β-diketone based side chain liquid crystalline polysiloxanes (DKLCP) with different length of flexible spacers and end groups have been synthesized by hydrosilation reaction. This is liquid crystal polymers (LCP) using coordinating β-diketone ligand as mesogens. The phase behaviour of DKLCP polymers was studied by differential scanning calorimetry and polarizing microscopy. X-ray diffraction investigations demonstrated that the polysiloxanes with sufficiently long flexible spacers were smectic liquid crystal polymers, while those with much shorter spacers were nematic ones.

溶胶-凝胶法制备的用于模式控制型液晶透镜的AZO高电阻薄膜

采用溶胶-凝胶法制备了掺杂摩尔分数为5%~20%的Al掺杂ZnO(AZO)高电阻薄膜,采用正方形电阻法表征了薄膜的方块电阻,采用扫描电子显微镜(SEM)对薄膜形貌进行了表征,采用Nano Measurer 1.2软件测量了薄膜晶粒的平均粒径,采用分光光度计表征了薄膜的光谱透过率。当Al掺杂摩尔分数为5%~20%时,方块电阻在2~405 MΩ/□之间逐渐增大,晶粒尺寸在24.35~17.53 nm之间逐渐减小,可见光透过率可达80%左右。制备了不同Al掺杂摩尔分数的AZO高电阻层的模式控制型液晶透镜并研究了其光学干涉特性,掺杂摩尔分数在10%~15%之间,AZO薄膜可满足液晶透镜对薄膜透明度和方块电阻的要求。

SYNTHESIS AND CHARACTERIZATION OF SIDE CHAIN LIQUID CRYSTATALLINE POLYSILOXANES CONTAINING BENZYL ETHER LINKING UNITS

Side chain liquid crystalline polysiloxanes containing benzyl ether linkingunits were synthesized by the hydrosilylation of poly (methylhydrosiloxane) with a series of4-(4-alkoxybenzyloxy)-4'-allyloxybiphenyl monomers [4-(4-methoxybenzyloxy )-4'-allyloxy-biphenyl(M_1), 4-(4-ethoxybenzyloxy)-4'-allyloxybiphenyl (M_2), 4-(4-propoxybenzyloxy)-4'-allyloxybiphenyl (M_3), 4-(4-butoxybenzyloxy)-4'-allylox(M_4), 4-(4-pentoxy-benzyloxy)-4'-allyloxybiphenyl (M_5), 4-benzyloxy-4'-allyloxybiphenyl (M_6)]. The phasebehavior of monomeric and polymeric liquid crystals was characterized by differential scan-ning calorimetry and optical polarization microscopy where the groups are ranged frommethoxy to pentoxy Both the monomeric and polymeric liquid crystals exhibit 1iquidcrystal behaviors.

基于光配向的主链型液晶聚合物预倾角的控制

液晶的方位角和预倾角的调制广泛应用于各类液晶光子器件的研究。液晶预倾角调控常使用的小分子液晶容易受外场干扰导致液晶预倾角的改变,影响液晶器件稳定性和可靠性。液晶聚合物具有相变温度高、耐热、耐强光、耐机械振动、更加稳定不易受外场干扰等优点,因此液晶聚合物预倾角的可控制备有着重要研究意义。由于液晶单体受液晶与空气界面的锚定能的影响,RM257液晶聚合物的预倾角与液晶层的厚度有关,难以实现预倾角的稳定可控。本研究利用两步法曝光偶氮染料亮黄(BY)薄膜诱导液晶单体RM257倾斜,采用多层旋凃及液晶单体RM257光聚合的方式降低液晶与空气界面锚定能对预倾角的影响,实现RM257主链型液晶聚合物预倾角可控制备。结果表明,采用这一方法制备的液晶聚合物薄膜预倾角可在0°~16°之间连续可调,并具有光热稳定的优点,具备实现液晶光子器件所需的图案化能力。本研究有望为液晶光子与显示器件的制备提供新的材料设计思路。

Effect of dichroic azo-dye doped on ferroelectric liquid crystals

In order to study the effect of mixing dye in ferroelectric liquid crystal （FLC） materials, the phase transition temperature and electro-optical properties of azo dye doped FLC samples have been investigated. All the properties have been found to be changed drastically. The results have revealed that not only the SmC^＊- SmA^＊ transition temperature decreased markedly by the addition of azo-dye, but also dye-doped FLC had lower threshold voltage and saturation voltage than the pure FLC.

基于定向电纺纤维膜的可调制偏振片的制备

基于定向静电纺丝技术制备了高取向性有序纤维薄膜,利用有序纤维对液晶分子取向的诱导,构建了可调制散射型偏振片.填充混合液晶的有序聚甲基丙烯酸甲酯纤维薄膜在可见光范围内,表现出明显的偏光特性.混合液晶中光敏性偶氮液晶4-正丁基-4′-甲氧基偶氮苯在360nm紫外光照射下进行顺反异构转变,诱导混合液晶发生从各向异性到各向同性的相变.利用混合液晶光致相变与有序纤维的耦合,实现了薄膜偏光特性的光控切换.

液晶器件用高二向色性偶氮染料的研究

通过重氮化反应和耦合反应合成了一种新的液晶显示用高二向色性偶氮染料A,用质谱、核磁共振谱对染料结构进行了表征,并研究了染料的二向色性和紫外吸收波谱。结果表明,染料A的二向色性D‖/D⊥达到7.5,λmax=475 nm。通过对A的分子结构改变,我们在A的基础上对A的尾链进行了改进,得到另一新的高二向色性偶氮染料A*,它的D‖/D⊥达到18.0,是目前报道过的二向色性染料材料的最高值。

新型可溶性偶氮聚酰亚胺及其作为液晶光定向层应用的初步研究

以 4 ,4′ 二 (1,2 苯二酸酐 4 羧酸酯 )偶氮苯为二酐单体 ,4 十六烷氧基 4′ ,4″ 二氨基三苯甲烷为二胺单体 ,通过缩聚反应合成了可溶性偶氮聚酰亚胺 .采用红外光谱、氢核磁共振、紫外光谱和热分析等手段 ,对产物的结构、热性能及光学性能等进行了表征 .在紫外光辐照下 ,上述聚合物表现出明显的光色效应 .经线性偏振紫外光 (LPUV)辐射后的上述偶氮聚酰亚胺定向层能诱导液晶盒中液晶分子发生定向沿面排列 ,且取向均匀 .上述实验表明 ,合成的偶氮聚酰亚胺是一类潜在的液晶光定向材料 .

偶氮液晶基元封端聚氨酯的合成与性能研究

以丁二酸酐、苯胺和对硝基苯胺为原料,经两步反应制得一种偶氮液晶基元(2);2与不同分子量的聚氨酯预聚体通过封端反应合成了一系列偶氮液晶聚氨酯(4a～4e),其结构和液晶性能经UV,NMR,FT-IR,TGA,DSC,POM和XRD等表征。结果表明,2从室温到熔点温度均表现出液晶态的强双折射。4a～4e为热致/溶致型液晶聚氨酯,具有较宽的液晶相温度区间。4的DMF溶液的临界浓度[w(4)]为3%～6%。

偶氮型液晶高分子的研究及应用

偶氮液晶高分子由于其具有特殊的光致异构和光致变色等光学性质,在光信息贮存材料、光开关材料和非线性光学设备材料等领域具有巨大的应用潜力,近年来得到了国内外研究者的广泛关注。本文概述了偶氮型液晶高分子的结构特征,详细介绍了主链型偶氮液晶高分子、侧链型偶氮液晶高分子、树枝状偶氮液晶高分子以及星型偶氮液晶高分子的研究现状及在光储存、光开关及光调制偏振片等方面的应用进展,指出了存在的问题和研究方向。

一代碳硅烷树枝状大分子钯配合物的液晶性

合成了新的周边含12个4-硝基偶氮苯端基一代碳硅烷树枝状大分子的钯(II)配合物(G1Pd),并用元素分析、核磁共振氢谱、碳谱、红外、紫外-可见光谱、能量色散X射线分析(EDXRA)、偏光显微镜、差示扫描量热法和广角X射线衍射法对其结构和液晶性质进行了表征.配合物G1Pd的相行为是K122ch189I166ch90K.给出一种具有新的结构特点的液晶性树枝状大分子,它兼有配位金属和介晶基元.在液晶和液晶高分子界观察到首例胆甾相的高强向错和首例树枝状大分子配合物的高强向错现象.

含二苯并-18-冠-6冠醚环的偶氮型液晶冠醚的合成

以4′-正烷氧基联苯-4-甲酸和顺(反)-4,4′-双(4-羟基苯基偶氮)二苯并-18-冠-6为原料,通过溶液缩合反应,合成了一系列新的偶氮型液晶冠醚,产率为91．7％-95．8％,产物经元素分析、核磁共振、紫外可见分光光度计、红外光谱、基质辅助激光解析电离飞行时间质谱、示差扫描量热法、偏光显微镜和X射线衍射表征。化合物4Ⅰ和4Ⅱ加热至各自的熔点以上都能形成液晶态,可以观察到近晶相和向列相(4ⅡD)的典型织构。随分子末端烷氧基碳原子数增加,化合物4Ⅰ和4Ⅱ的熔点(Tm)和液晶态的清亮点(Ti)逐渐降低,液晶态的温度范围较宽。

光场与掺杂向列相液晶薄膜相互作用的若干问题

从激光与掺杂液晶薄膜相互作用的角度,介绍了掺杂液晶非线性光学的多个不同侧面,阐述了光场诱导液晶分子指向矢的重新取向问题、偶氮物掺杂液晶超大光学非线性问题、以及掺杂液晶光限幅的研究现状和进展。

二向色性偶氮染料掺杂胆甾相液晶光阀的电光性能研究

为了制得既能够提供黑色同时又具备高透过率的光阀,本文制备了一种能在反射态和透明态之间切换的主动电场可控性液晶光阀。该光阀主要选用3种偶氮类二向色性染料掺杂螺距位于红外区的胆甾相液晶,并详细地研究了螺距对液晶光阀电光性能的影响。实验结果表明:随着螺距的增大,Vth、Vsat和ton均逐渐减小,其中,最大的Vth和Vsat分别仅为6V和20V左右,ton也仅为0.878ms,并且该薄膜的透过率在电场的作用下可达80%以上。因此,所制备的DDCLC薄膜既满足了透明显示面板高透过率的要求,又提高了其能见度。