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反铁电性液晶化合物研究现状 总被引:7,自引:0,他引:7
综述了反铁电性液晶近年来的研究现状, 讨论了反铁电性液晶结构中各部分对液晶相变行为和电光性能的影响, 简要论述了反铁电性液晶今后的研究方向。 相似文献
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具有液晶相态特征的功能化梯形聚硅氧烷 总被引:8,自引:0,他引:8
介绍了几种具有液晶相态特征的功能化梯形聚硅氧烷,包括β-二酮、西夫碱、偶氮3种类型液晶侧链的“鱼骨形”液晶高分子和相应的金属络合型液晶高分子以及挂接发色团的非线性光学梯形高分子。它们是由反应性聚氢基倍半硅氧烷及其共聚物与功能性单体进行硅氢加成反应来合成的。“鱼骨形”液晶高分子与小分子液晶组成高分子网络液晶(PNLC)型的复合物,表现出有趣的正性或负性两种不同的电光响应行为,与“锚泊效应”和弹性有关。非线性光学梯形高分子的极化膜表现了稳定的极化诱导取向。高温下稳定的双折射光带为这类梯形高分子共同的相态特征之一。可控孔径尺寸的笼状自组装超分子膜及其与有机小分子构成的分子级功能复合膜为逐步偶联聚合方法的另一重要发展方向。 相似文献
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以4-羟基联苯,4-羟基4’-氰基联苯和手性L-2-甲基丁醇为原料,通过三条路线合成了铁电性液晶中间体4-羟基联苯4’-甲酸-L-2-甲基丁醇酯。5步法(醚化、酰化、溴仿、水解和酯化)总收率35.6%;3步法(酰化、溴仿和酯化)总收率50.7%;而以4-羟基-4'-氰基联苯为原料的一步合成法收率64.4%。中间体和目标产物的结构经^1H NNR和IR确证。 相似文献
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侧链液晶高分子的非线性光学特征及其应用 总被引:4,自引:2,他引:4
阐述了侧链高分子液晶非线性光学的基本原理,着重讨论了影响非线性光学特征的几个基本因素,说明了双折射与外场强度、双折射与序参数之间的定量关系,展望了侧链高分子液晶非线性光学特征在一些领域中的应用前景。 相似文献
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Peiyang Gu Xufeng Xu Feng Zhou Tingting Zhao Gaojie Ye Gaoyan Liu Qinghua Xu Jianfeng Ge Qingfeng Xu Jianmei Lu 《中国化学》2014,32(3):205-211
Four 1,8‐naphthalimide hydrazone molecules with different electron‐donating groups have been applied in the study of linear and nonlinear optical (NLO) properties. These compounds showed strong green emission in solution. Their NLO properties such as two‐photon absorption (TPA) behavior with femtosecond laser pulses ca. 800 nm and excited‐state absorption (ESA) behavior with nanosecond laser pulses at 532 nm were investigated. Compound 4 presented the largest two‐photon cross section (550 GM) among them due to two factors: the conjugated length of compound 4 is the longest and the electron‐donating ability of compound 4 is the strongest. Different from TPA behavior, compound 2 showed the best nonlinear absorption properties at 532 nm and its nonlinear absorption coefficient and third‐order nonlinear optical susceptibilities χ (3) were up to 1.41×10?10 MKS and 4.65×10?12 esu, respectively. Through the modification of the structure, the nonlinear optical properties of these compounds at different wavelengths (532 and 800 nm) were well tuned. The great broad‐band nonlinear optical properties indicate hydrazones are good candidates for organic nonlinear optical absorption materials. 相似文献
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David J. Williams 《Angewandte Chemie (International ed. in English)》1984,23(9):690-703
Nonlinear optical properties are a sensitive probe of the electronic and solid-state structure of organic compounds and as a consequence find various applications in many areas of optoelectronics including optical communications, laser scanning and control functions, and integrated optics technology. Because of their strongly delocalized π electronic systems, polymeric and non-polymeric aromatic compounds show highly nonlinear optical effects. Nowadays, polymer chemists are able to tailor specific materials properties for various applications. Some organic substances with π electronic systems exhibit the largest known nonlinear coefficients, often considerably larger than those of the more conventional inorganic dielectrics and semiconductors, and thus show promise for thin-film fabrication, allowing the enormous function and cost advantages of integrated electronic circuitry. The electronic origins of nonlinear optical effects in organic π electronic systems are reviewed, with special emphasis being given to second-order nonlinear optical effects. Methods for measuring nonlinear optical responses are outlined, and the critical relationships of the propagation characteristics of light to observed nonlinear optical effects and to solid-state structure are discussed. Finally, the synthesis and characterization of organic crystals and polymer films with large second-order optical nonlinearities are summarized. 相似文献
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P. R. Srikanth Sharma Peiguang Zhou Harry L. Frisch 《Journal of polymer science. Part A, Polymer chemistry》1996,34(6):1049-1058
We report the synthesis and characterization of interpenetrating polymer networks (IPNs) exhibiting nonlinear optical (NLO) properties. The network consists of aliphatic polycarbonate urethane (PCU) and poly(methyl methacrylate-co-N,N-disubstituted urea), with a nonlinear optical (NLO) chromophore incorporated into N,N-disubstituted urea. The full IPNs have only one Tg, as determined by differential scanning calorimetry (DSC), together with scanning electron microscopy (SEM) observations, suggest a single phase morphology. The thin films of IPNs are transparent and the unpoled samples produced second harmonic generation (SHG) signals at room temperature. This result indicates that the NLO chromophore is oriented noncentrosymmetrically during the IPN formation process and is tightly held between the permanent entanglements of the two component networks of the IPN. © 1996 John Wiley & Sons, Inc. 相似文献
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Kimihiro Yuasa Shunji Uchida Takashi Sekiya Kenji Hashimoto Kenji Kawasaki 《先进技术聚合物》1992,3(5):205-209
Ferroelectric liquid crystalline polymers (FLCPs) were synthesized. These ferroelectricities were confirmed directly by measuring polarization reversal currents and other electro-optical properties. The smectic layer structure of FLCP was also studied. A chevron structure similar to that of low molecular weight FLC was observed even in an FLCP cell; but the zigzag defects were not so sharp, which means that it is easy to obtain a good orientation even in large-area displays. 相似文献
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介绍了非线性光学性质的原理以及目前研究的具有这种特殊性质的功能材料的结构特点和应用. C60具有的特殊结构, 使其在众多领域成为了研究的重点. C60本身就具有良好的非线性光学性能, 对其修饰得到的各种衍生物更体现优良的性质, 尤其是目前人们大量研究的富勒烯高分子化功能材料具有非常快速的非线性响应时间. 因此重点介绍了C60及其衍生物的结构、非线性光学原理、性质和国内外最新的研究状况. 相似文献
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Dr. Wen-Wen Yang Dr. Jun-Jian Shen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(65):e202202069
Multiple heterohelicenes are a unique class of helical nonplanar scaffolds that have attracted great attention due to their appealing shapes, optical and electronic properties, and potential applications in chiral materials. This review describes the recent advances and challenges in the design and synthesis of representative multiple heterohelicenes with intriguing chiral properties. And the corresponding applications are also covered. 相似文献
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Wen-Chang Chen Samson A. Jenekhe Jeffrey S. Meth Hermann Vanherzeele 《Journal of Polymer Science.Polymer Physics》1994,32(1):195-200
An investigation of the refractive index and third-order nonlinear optical susceptibility χ(3) of two polypernigraniline derivatives, poly (4,4'-diphenylimine methine) (PDPIM) and poly (4,4'-diphenylimine p-heptyloxybenzylidene) (PDPIHB) reveals effects of molecular structure on the linear optical and nonlinear optical properties of conjugated polymers. The χ(3) (?3ωω,ω,ω) of PDPIM was found to decrease relative to polypernigraniline, reflecting the observed decrease of the oscillator strength of the 2.2 eV absorption band when a methine carbon replaces one of the nitrogen atoms of pernigraniline repeat unti. The alkoxyphenylene side group substitution at the methine carbon in PDPIHB, however, significantly enhances the nonlinear optical response of PDPIHB while reducing the refractive index compared to PDPIM and polypernigraniline. The present results suggest that structural changes in conjugated polymers can be made in such a way as to enhance the nonlinear optical properties while modulating the linear optical properties. © 1994 John Wiley & Sons, Inc. 相似文献
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The fully oxidized state of polyaniline (PANI), pernigraniline (PN), was synthesizedby oxidation of the emeraldine base form of PANI dissolved in NMP solvent with m-chloroperoxybenzoic acid. The resulted PN was characterized by FTIR and UV-Visiblespectra. The third-order nonlinear optical properties of PN in concentrated sulfuric acid(PN/H_2SO_4) were measured by a degenerated four wave mixing (DFWM) method. The re-sults obtained suggest that the soliton-pair intermediate state associated with thedegenerated state does not play a major role in the third order nonlinear optical prop-erties of PANI. 相似文献