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1.
反铁电性液晶化合物研究现状   总被引:7,自引:0,他引:7  
范星河  周其凤 《化学进展》2001,13(4):251-256
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   

2.
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   

3.
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   

4.
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   

5.
手性丙烯酸酯液晶原位光聚合反应何流,张树范,金顺子,漆宗能,王佛松(中国科学院化学研究所北京100080)关键词手性丙烯酸酯,原位光聚合,双折射,近晶相手性侧链液晶高分子显示近晶S!相,具有铁电性,在光电功能材料和非线性光学材料方面有潜在的应用前景’...  相似文献   

6.
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 NMR和IR确证.  相似文献   

7.
通过简单的“A2+B3”反应,我们成功地合成了一个新的超支化非线性光学高分子。同时,作为对比,我们还合成了相对应的线型高分子。制备的两个高分子均溶于常见的有机溶剂,并由各种表征手段予以鉴定。超支化高分子的二阶非线性光学性能极大地优于相对应的线型高分子,表明超支化结构有利于提高高分子材料的宏观非线性光学效应。  相似文献   

8.
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。  相似文献   

9.
《离子交换与吸附》2007,23(5):F0004-F0004
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]  相似文献   

10.
含偶氮基团的侧链液晶高分子的研究进展   总被引:3,自引:0,他引:3  
综述了含偶氮基团的侧链液晶高分子的制备方法及其在可逆光信息存储与非线性光学领域的应用。  相似文献   

11.
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   

12.
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   

13.
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   

14.
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   

15.
二阶非线性光学聚合物材料的最新研究进展   总被引:1,自引:0,他引:1  
随着激光技术与光纤通信技术的蓬勃发展 ,迫切要求提高非线性光学极化聚合物的性能 ,以满足器件化的要求 ,这就需要从分子设计和极化方法等方面进行研究和优化。本文以聚合物主链结构为线索 ,以非线性光学性能为依据 ,介绍了二阶非线性光学聚合物的最新研究进展 ,并展望了该类聚合物在光通信领域的应用前景  相似文献   

16.
陈薇  曾和平 《有机化学》2007,27(1):8-16
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   

17.
含偶氮苯光学活性侧基聚合物研究进展   总被引:11,自引:0,他引:11  
综述了含偶氮苯光学活性侧基聚合物近年来的发展概况 ,介绍了多种聚合体系的类型。由于偶氮苯光于活性侧基的存在 ,使得这些聚合物具有光致变色性、非线性光学活性、光学各向异性等光学性能 ,在光信息存储材料、非线性光学材料、液晶材料、光电子器件、生物分子活性光调控、纳米技术等诸多领域都有广泛的应用。  相似文献   

18.
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   

19.
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   

20.
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   

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