基于扭曲晶界A相/胆甾相共存的液晶复合材料的制备及宽波反射性能研究

Cholesteric liquid crystal composites with higher clearing point will be prepared. The influences of the chemical structures and the compositions of chiral compounds on the compatibility of chiral compounds and nematic liquid crystals, the temperature range of cholesteric phase will be investigated. Furthermore, liquid crystal composite materials with wider temperature range of twist grain boundary A phase will be prepared. The influences of the chemical structures and the compositions of chiral compounds, nematic liquid crystals and smectic liquid crystals, the temperature range of smectic phase and cholesteric phase on the temperature range of twist grain boundary A phase, the pitch length and the reflection wavelength will be investigated. Liquid crystal composite materials based on the coexistence of twist grain boundary A and cholesteric phase will be prepared by stepwise UV polymerization. The influences of the chemical structures and the compositions of each component, UV light intensity and time, curing temperature on the microstructures of polymer network will be investigated. Furthermore, the influences of the microstructures of polymer network, microdistributions of pitch, the chemical structures and the compositions of each component on the broadband reflectance properties of liquid crystal composite materials based on the coexistence of twist grain boundary A and cholesteric phase will be investigated, and the correlative mechanisms will be revealed, to provide the experimental method and theoretical guidance for broadband reflective liquid crystal materials with different reflection wavelength and wavelength range.

调制具有较高清亮点温度的胆甾相（Ch相）液晶复合材料，研究手性化合物的化学结构及组成等因素对手性化合物与向列相（N相）液晶的相容性、Ch相温域的影响规律。进一步调制具有较宽扭曲晶界A相（TGBA相）温域的液晶复合材料，研究手性化合物、N相及SmA相液晶的化学结构及组成、液晶复合材料中SmA相和Ch相的温域等因素对TGBA相温域、螺距尺寸及反射波长的影响规律。采用紫外分步聚合的聚合方式，制备TGBA相/Ch相共存的液晶复合材料，研究液晶复合材料中各组分的化学结构及组成、紫外光照射强度及时间、聚合温度等因素对聚合物网络的微观结构的影响规律，进一步研究液晶复合材料中聚合物网络的微观结构、螺距微区分布、各组分材料的化学结构及组成等因素对TGBA相/Ch相共存的液晶复合材料的宽波反射性能的影响规律，并揭示相关机理，为开发可适用于不同反射波长及反射波宽的液晶宽波反射材料提供实验方法和理论依据。

制备了近晶A相（SmA相）-胆甾相（Ch相）液晶单体SCM、SmA相液晶单体CLSB及Ch相液晶单体DCM，利用核磁共振波谱（1H-NMR）以及基质辅助激光解吸电离-飞行时间质谱（MALDI-TOF-MS）证实了制备的SCM、CLSB及DCM为预期的化学结构。采用差示扫描量热仪（DSC）测试了SCM、CLSB及DCM的相转变温度。.采用制备的SCM与SLC1717调制具有较宽TGBA相温域的SCM-SLC1717二元液晶复合体系。研究了SCM与SLC1717的比例对二元液晶复合体系的扭曲晶界A相（TGBA相）温域的影响，当SCM与SLC1717比例为35:65、40:60、45:55时，二元液晶复合体系中TGBA相温域较宽，分别为4.0oC、8.4oC和5.3oC，在三组二元液晶复合体系的基础上，添加不同含量的8OCB，调制具有更宽TGBA相温域的SCM-SLC1717-8OCB三元液晶复合体系，采用DSC及POM对调制的三元液晶复合体系的TGBA相温域进行了测试，当SCM与SLC1717比例为40:60，8OCB在液晶复合体系中所占比例为30%时，三元液晶复合体系中TGBA相温域较宽，为11.2oC。在该三元液晶复合体系中添加手性化合物R5011，当R5011的用量为1.5%时，初始反射波位从400 nm开始，整个降温过程中反射波位的移动范围可以覆盖整个可见光区域。.采用制备的CLSB、DCM调制具有较宽TGBA相温域的CLSB/SLC1717/C6M/DCM/DGEBF/IRG651/CPI液晶复合体系，研究了液晶复合体系的相转变行为和反射特性。采用该液晶复合体系，通过紫外分步聚合的聚合方式分别固定Ch相的小螺距和TGBA相的大螺距制备了液晶宽波反射材料，并系统地研究了聚合条件对液晶宽波反射材料反射波宽的影响。为液晶宽波反射材料的制备及宽波反射性能的研究开辟一条新的途径。