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1.
Rotational viscosity of a liquid crystal mixture: a fully atomistic molecular dynamics study 下载免费PDF全文
Fully atomistic molecular dynamics (MD) simulations at 293, 303 and
313~K have been performed for the four-component liquid crystal
mixture, E7, using the software package Material Studio. Order
parameters and orientational time correlation functions (TCFs) were
calculated from MD trajectories. The rotational viscosity
coefficients (RVCs) of the mixture were calculated using the
Nemtsov--Zakharov and Fialkowski methods based on
statistical-mechanical approaches. Temperature dependences of RVC
and density were discussed in detail. Reasonable agreement between
the simulated and experimental values was found. 相似文献
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Both polymer stabilization and bent-shaped molecule doping strategies are utilized to widen the blue phase range of liquid crystals. The molecular structures of compositions are optimized for high thermo-optical and electro-optical performances. A low temperature applicable blue phase liquid crystal with suppressed hysteresis is achieved. The bistability of one blue phase liquid crystal is investigated. Based on these materials, fast tunable devices such as gratings with polarization insensitivity are designed and fabricated. The materials and device designs demonstrated here are suitable in wide applications requiring fast response time. 相似文献
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采用一次性全息曝光的方法同时在样品上制备了周期分别为1μm和4μm,衍射效率电场可调的双重复合式液晶/聚合物光栅.使用He-Ne激光器对复合光栅的衍射特性进行了实验研究,发现光栅存在两个1级衍射极强峰.对峰值衍射效率的测定结果表明,周期1μm的光栅衍射效率为90%,周期4μm的光栅,60%.结合耦合波理论计算了周期1μm和4μm光栅的衍射效率理论值,分别为92.57%和63.68%.实验结果与理论值符合得非常好.对电光特性的测试表明该复合光栅内的两套子光栅的驱动电压V90关键词:
光栅
液晶 相似文献
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制备了不同单体浓度的聚合物稳定铁电液晶器件,测试了震动实验和热稳定实验前后样品的排列织构、电光特性和对比度.用原子力显微镜研究了各样品的聚合物形貌,表明在器件内部形成了沿摩擦方向延伸的聚合物网络,并且随着单体含量的增加聚合物网络更加致密.由于聚合物网络体锚定的引入,使得铁电液晶分子在外力和温度场下的运动受到限制,聚合物体锚定的增强使聚合物稳定铁电液晶的稳定性也逐渐提高.实验结果表明,单体含量为4%时,聚合物稳定铁电液晶的抗震性和热稳定性良好,电光曲线为无阈值“V”字型,对比度达150∶1. 相似文献
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Electro-optical properties of polymer stabilized cholesteric liquid crystal film 总被引:1,自引:0,他引:1 下载免费PDF全文
Liquid crystals (LCs) and polymers are extensively used in various electro-optical applications.In this paper,normal mode polymer stabilized cholesteric LC film is prepared and studied.The effects of chiral dopant and monomer concentrations on the electro-optical properties,such as contrast ratio,driving voltage,hysteresis width and response time,are investigated.The reasons of electro-optical properties influenced by the concentrations of the materials are discussed.Through the proper material recipe,the electro-optical properties of polymer stabilized cholesteric LC film can be optimized. 相似文献
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使用3种不同化学结构的单体材料制备了全息聚合物分散液晶光栅,并从光栅形貌、衍射能力、驱动特性、聚合物热稳定性4个方面评价了光栅的热稳定性.研究发现,含有刚性结构单体材料体系的光栅形貌、衍射能力等方面在200℃的温度下没有明显变化.表明光栅的热稳定性与单体材料的化学结构密切相关,单体材料中含有刚性结构有助于光栅热稳定性的提高.利用热重分析(TGA)对光栅中聚合物材料热分解温度进行了测定,并结合Freeman-Carroll微商法计算出了上述聚合物的分解活化能和分解反应级数.结果发现,含有刚性结构的聚合物材料的热分解温度、分解活化能和分解反应级数都高于柔性链结构材料,进一步验证了材料体系中刚性结构的添加有助于提高光栅的热稳定性. 相似文献
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Kinetics investigations for holographic Bragg gratingbased on polymer dispersed liquid crystal 下载免费PDF全文
This paper investigates the monomer kinetics of polymer dispersed
liquid crystal (PDLC) grating. Fourier transform infrared (FTIR)
spectra are used in the studies of photoreaction kinetics. The
results indicate that there is a relative stable stage arises after
a very short initial stage. Based on FTIR studies, the monomer
diffusion equation is deduced and necessary numerical simulations
are carried out to analyse the monomer conversion which is an
important point to improve phase separation structure of PDLC
grating. Some simulation results have a good agreement with
experimental data. In addition, the effects induced by monomer
diffusion constant $D$ and diffusion--polymerization-ratio rate $R$
are discussed. Results show that monomer conversion can be improved
by increasing value of $D$. Besides, a good equilibrium state
($R=1$) is more beneficial to the diffusion of monomer which is
important in the process of phase separation. 相似文献