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91.
The synthesis of a new chiral mesogenic monomer ( M1 ), a nematic monomer ( M2 ), and a series of side chain cholesteric copolymers ( P2 – P6 ) containing the mesogenic menthyl groups is described. The chemical structures of the compounds were confirmed by FTIR and 1H NMR. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, thermogravimetric analysis, and polarizing optical microscopy. M 1 showed an enantiotropic cholesteric phase, and M2 revealed a nematic phase. The homopolymers P1 and P7 , respectively, displayed a chiral smectic A (SA) phase and a nematic phase, while the copolymers P2 – P6 exhibited the Grandjean texture of the cholesteric phase. Tg, Ti, and ΔT of P1 – P7 increased with increasing the concentration of M2 in the polymers. All of the obtained polymers displayed very good thermal stability and the wide mesophase temperature range. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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扭曲相液晶由外场引起的形变 总被引:2,自引:2,他引:0
在具有水平锚定的扭曲相液晶盒中沿表面法线加一外电场. 此外电场可产生3种指向矢形变 (1)均匀形变, 在这一形变中, 指向矢只沿垂直于表面的坐标轴变化; (2)周期性形变, 在这一形变中指向矢沿表面某一轴呈周期性变化; (3)平面内扭曲, 液晶螺旋轴从平行于表面法线方向, 旋转90°至平行于表面. 计算了这3种形变的电场域值, 并获得相图. 结果表明平面内扭曲形变的产生主要由于是弱锚定边界条件, 并与液晶的螺旋性有关. 降低锚定强度, 可使系统从均匀形变相或周期性形变相进入平面内扭曲形变相. 周期性形变相和均匀形变相之间的相变主要由系统的弹性系数和螺距决定. 在螺距较大时, 周期性形变出现在较小的弹性系数比K11/K22. 相似文献
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Rafael S. Zola Hossein Nemati Young‐Cheol Yang Deng‐Ke Yang Chao‐Chiun Liang Kung‐Lung Cheng Frank Shiu Chen‐Chu Tsai 《Journal of the Society for Information Display》2013,21(1):22-28
In this article, we report our study of a dual mode reflective cholesteric display, which works in the traditional bistable mode as well as in the new and fast monostable mode. Because both modes are compatible, they can be used according to the need for video or static images. The bistable mode operates between the reflecting planar state and non‐reflecting focal conic state, both of which are stable at zero voltage. The bistable mode is suitable for displaying static images. In the monostable mode, it is operated on wrinkled cholesteric layers. It is fast and has low driving voltage, and can exhibit gray levels of reflectance determined by the applied voltage. The monostable mode is suitable to display video rate dynamic images. 相似文献
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液晶盒边界效应对胆甾相液晶电控螺距的影响 总被引:1,自引:1,他引:0
研究了共面转换(IPS)液晶盒处于强锚定及弱锚定两种边界状态时横向电场与平面织构胆甾相液晶螺距的关系,探讨了液晶盒表面锚定对胆甾相液晶电控螺距的影响。理论结果表明,共面转换模式下电场可以调谐胆甾相液晶的反射光颜色,而边界锚定效应对电场调谐螺距有显著影响。这一结果为基于电控螺距原理的胆甾相液晶反射式彩色显示方案提供了理论上的依据。 相似文献
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The ability to tune molecular self‐organization with an external stimulus is a main driving force in the bottom‐up nanofabrication of molecular devices. Light‐driven chiral molecular switches or motors in liquid crystals that are capable of self‐organizing into optically tunable helical superstructures undoubtedly represent a striking example, owing to their unique property of selective light reflection and which may lead to applications in the future. In this review, we focus on different classes of light‐driven chiral molecular switches or motors in liquid crystal media for the induction and manipulation of photoresponsive cholesteric liquid crystal systems and their consequent applications. Moreover, the change of helical twisting powers of chiral dopants and their capability of helix inversion in the induced cholesteric phases are highlighted and discussed in the light of their molecular geometric changes. 相似文献