双稳态液晶显示技术的研究进展

双稳态液晶显示器件具有节能、轻便、可柔性化等优点,在便携显示设备如电子书、智能卡、写字板和射频标签等领域具有重要的应用价值。本文按热致液晶的3个相态胆甾相、近晶相和向列相分别介绍了它们的双稳态显示原理、显示模式和最近的研究进展。     

含异山梨醇结构的液晶用手性搀杂剂的应用研究

介绍了胆甾相液晶显示(Ch-LCD)原理和对液晶材料的要求,分析了近年来对用于胆甾相液晶材料的含异山梨醇的手性搀杂剂的一些研究,初步阐述了该类手性搀杂剂的结构与液晶性能及在液晶材料中的应用前景。     

胆甾液晶齐聚物/聚二甲基硅氧烷橡胶复合膜的制备及血液相容性研究

将2种胆甾液晶单体接枝到含氢聚硅氧烷上制备了胆甾液晶齐聚物,并将此齐聚物与聚二甲基硅氧烷复合制备了一系列复合膜.以偏光显微镜观察了不同液晶含量对复合膜的表面结构形态的影响.通过溶血实验和动态凝血实验研究了其血液相容性,结果表明改性的复合膜具有很好的血液相容性.表面接触角的测定表明复合膜的亲水性由于聚二甲基硅氧烷表面胆甾液晶相的存在得到明显改善.     

胆甾液晶高分子的研究及信息领域的潜在应用

胆甾液晶高分子兼具胆甾相液晶的独特光学性质及高分子的特点从而具有广泛的应用前景。本文在介绍胆甾相液晶独特的螺旋状分子结构和光学性能的基础上,概括了热致侧链胆甾高分子(ChSLCP)的结构及其对性能的影响,并介绍其在光信息记录方面的研究进展。     

纤维素衍生物/二氯乙酸液晶溶液的织态结构[摘]

纤维素衍生物,如乙基纤维素,甲基纤维素,乙基氰乙基纤维素,乙基醋酸纤维素等与二氯乙酸所形成的溶液在浓度达到临界值以上后,出现胆甾型液晶相。在这类溶液中,液晶相的织态结构具有多重性,即胆甾型液晶相的织构随溶液浓度和温度而变化。在不同的浓度范围内,溶致性液晶可呈现出圆盘织构,条纹织构,假各向同性织构和具有鲜艳色彩的平面织构。这些织构均具有胆甾型液晶的特征。在液晶相刚形成,溶液处于     

含氟甾体液晶研究

以含氟基团改造3β及17β位置的端基短链,研究结构与液晶性的关系,利用液晶核的碳原子手性结构,开发胆甾相含氟液晶,探讨开发胆甾相液晶材料的可能性。将氟代芳基和全氟烷基等含氟官能团引入甾类液晶的3β-取代基中,以考察对构效关系的影响;利用的猪去氧胆酸是易得的天然甾体之一,能较为便捷地转化为具有平面构型的3β-羟基-5-胆烯酸,通过不同的方法改造其17-侧链,可考察不同基团对其构效关系的影响。以附有加热台的偏光显微镜及差示扫描量热法用来分析液晶相变化。结果发现有多种高清亮点的含氟胆甾相液晶可作为胆甾相液晶混合物的添加剂使用。     

简单的振动使液晶由透明状态转变为镜面状态

<正>一种随施加电压的增加而反射不同颜色光的液晶装置可从透明状态转变为几近镜面状态。据开发者介绍,这种可调镜面物质可用来制造智能窗户,夏天阻隔热量,冬天让热量进入,它还可以为在室内外环境中不断切换的平板电脑屏幕提供材料。位于俄亥俄州的美国空军研究实验室的Timothy J.White及其同事利用胆甾相液晶(CLCs)制备出了该镜面材料。胆甾相液晶是由     

一种新的双液晶基元化合物的合成与表征

合成了一种新的胆固醇酯基双液晶基元化合物,另一端液晶基元为4-苯甲酸(4′-甲氧基苯基)酯基,2个液晶基元通过丁二酸酯键相连。该双液晶基元化合物在加热和冷却过程中都在较宽的温度范围内出现胆甾相液晶,并随着温度的变化呈现鲜艳的颜色变化(170~227℃或222~87℃)。这种液晶化合物可能在液晶显示、铁电性或反铁电性液晶器件上有一定的应用前景。     

光活性联苯酯类液晶研究：液晶性能及织构转变

将手性碳原子引入分子结构,合成了6个具有光学活性的联苯酯类液晶,用旋光检测、XRD、DSC、POM等对其进行表征,结果表明6个化合物都是胆甾型互变液晶,液晶性能良好;柔性端基链的增长有利于胆甾相指纹织构的稳定存在,端基链最长的化合物存在焦锥织构和指纹织构间的可逆转变。     

一种新型四液晶基元化合物的合成及其液晶性能

合成了一种新型的四液晶基元化合物,其分子中含有2个胆固醇基团和2个席夫碱基团,这4个液晶基元以柔性间隔段相连,使用热台偏光显微镜(POM)和差示扫描量热法(DSC)对该四液晶基元化合物的液晶性能进行了表征,结果表明它在加热过程中较宽的温度范围内(198～307℃)形成胆甾相液晶.     

Synthesis and characterization of novel monomers and polymers containing chiral (−)-menthyl groups

To investigate the steric effects of chiral menthyl groups on the induction of cholesteric liquid crystals and the sensitivity of the photoisomerizable azobenzene derivatives, a series of chiral monomers and a photoisomerizable chiral azobenzene derivative with various spacers end-capped with (−)-menthyl group were synthesized. The structures of the novel chiral compounds synthesized in this investigation were identified using ¹³C NMR, FTIR, and elemental analysis. The phase transition temperatures of the chiral compounds were investigated using X-ray diffraction, differential scanning calorimetry, and polarizing optical microscopy. The thermogravimetric characteristics, the glass-transition temperatures (T_g) and the weight-average molecular weights (M_w) of the homopolymers were also evaluated. Polymers containing chiral menthyl groups with a biphenyl segment were found to reveal high thermal resistance. However, the existence of the steric hindered menthyl group disturbed the arrangement of chiral monomers leading to the disappearance of liquid crystal phases. The specific optical rotation of the synthesized monomers and polymers were also evaluated. The effect of the synthesized chiral compounds, monomers and photoisomerizable azobenzene derivative on the induction of the cholesteric liquid crystal films was investigated. The morphological network structure of the polymer matrix inside a liquid crystal cell was studied using a scanning electron microscope (SEM). The phototuning ability of the AzoM on the cholesteric liquid crystals was also established.     

电子纸技术及其应用

综述了电泳显示、旋转球显示和液晶显示及其他电子纸在彩色化、高反差、低能耗、快速响应等方面的研究进展,介绍了各种原理型显示技术的优缺点。纳米颗粒电泳、胆甾液晶、有机电致发光、隐色染料显示、无机电致发光等原理显示技术的开发,以及导电高分子薄膜晶体管的应用,使电子书、智能显示卡、无墨印刷、电子报纸等技术应用逐步成为现实。指出具有柔性、节能及大视角等特点的电泳显示、旋转球显示、有机电致发光电子纸是近几年的主要研究内容。     

Magneto-optically active polythiophene derivatives bearing a stable radical group from achiral monomers by polycondensation in cholesteric liquid crystal

Chiral π-conjugated polymers bearing a stable radical group are successfully prepared by chiral inductive asymmetric polymerization using a cholesteric liquid crystal medium. The polymers thus synthesized form “structural chirality”, with the structure of the polymer being analogous to that of the one-handed helical form of the cholesteric liquid crystal. Chirality and magnetic properties of the present polymers were elucidated.     

我国手性液晶的研究进展与应用

阐述了手性液晶的结构和分类,介绍了近年来国内手性液晶的合成与研究进展情况,并着重讨论了胆甾相手性液晶的热色效应及其作为手性添加剂在显示领域的应用以及铁电液晶的非线性光学效应.     

Continuous spatial tuning of laser emissions in a full visible spectral range

In order to achieve a continuous tuning of laser emission, the authors designed and fabricated three types of cholesteric liquid crystal cells with pitch gradient, a wedge cell with positive slope, a wedge cell with negative slope, and a parallel cell. The length of the cholesteric liquid crystal pitch could be elongated up to 10 nm, allowing the lasing behavior of continuous or discontinuous spatial tuning determined by the boundary conditions of the cholesteric liquid crystal cell. In the wedge cell with positive slope, the authors demonstrated a continuous spatial laser tuning in the near full visible spectral range, with a tuning resolution less than 1 nm by pumping with only a single 355 nm laser beam. This continuous tuning behavior is due to the fact that the concentration of pitch gradient matches the fixed helical pitch determined by the cell thickness. This characteristic continuous spatial laser tuning could be confirmed again by pumping with a 532 nm laser beam, over 90 nm in the visible spectral range. The scheme of the spatial laser tuning in the wedge cell bearing a pitch gradient enabled a route to designing small-sized optical devices that allow for a wide tunability of single-mode laser emissions.     

Mixed solvent and polyacrylamide-blended ethylcellulose liquid crystals

The mesophase behaviours of mixed solvent cellulosic liquid crystal systems, ethylcellulose/acrylic acid+water (EC/AA+W), ethylcellulose/acrylic acid+glacial acetic acid (EC/AA+GAA) and of ethylcellulose/acrylic acid systems blended with a flexible polymer, polyacrylamide (PAM+EC/AA), have been studied. The critical concentrations decreased in all the systems compared with the pure EC/AA system and the morphologies were affected, but still cholesteric. The cholesteric properties varied with composition of solvent and polymers. ©1997 SCI     

Interfacial conversion for poly(para‐phenylenevinylene) at a cholesteric liquid crystal surface

A new approach for the preparation of poly (para‐phenylenevinylene) (PPV) with an ordered structure is presented. PPV is synthesized by a precursor method using a cholesteric liquid crystal medium. The resultant PPV film is observed to have a cholesteric fingerprint‐like texture, indicating replication of the cholesteric liquid crystal medium. Infrared absorption measurements confirm that the PPV has essentially the same molecular structure as normal PPV film. Ultraviolet–visible absorption measurements show that the absorption band due to π?π* transition of the conjugated main‐chain is located at 402 nm. The conversion is found to occur at the interface with the cholesteric liquid crystal medium as a mechanical process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

高效酰化催化法合成新型胆甾醇酯液晶

采用高效酰化催化法和酰氯化法分别合成了燕尾型胆甾醇酯和对称脂肪族二羧酸胆甾醇酯两类衍生物样品。采用元素分析、红外光谱、DSC、热台偏光显微镜对样品的化学结构和液晶性能进行了表征。3个对称脂肪族二羧酸胆甾醇酯样品均为胆甾型液晶,而燕尾型的支链结构对胆甾醇酯液晶的形成具有不利的影响。两种合成胆甾醇酯的酰化方法经过对比表明,高效酰化法具有反应条件温和、副反应小、不破坏反应物、产物易分离、产率高等优点,可作为胆甾醇酯液晶合成的首选方法。