利用紫外-可见分光光度计,X射线衍射仪与偏光显微镜研究了乙基纤维素(EC)与羟丙基纤维素(HPC)共混型胆甾液晶.研究发现:质量百分浓度相同时,共混纤维素胆甾型液晶的最大反射波长与螺距随着共混物中HPC含量的增加而增大.XRD实验结果表明共混型纤维素液晶螺距增大与液晶体系中分子层间的距离增大相关.可以利用该现象来调控纤维素胆甾型液晶的光学性能与螺距.
The cholesteric liquid crystals of the blend of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC) with different percentages were prepared and characterized by using UV-vis spectrometer, XRD spectrometer and polarized microscope. With the increasing of the percentage of HPC in the blend, when the weight concentrations of the blend liquid crystals are the same, the pitch and the maximum wavelength of selective reflection of the blend liquid crystals are increased. It is confirmed that the increasing of the pitch and the maximum wavelength of selective reflection is related to the increasing of the distance of the cholesteric liquid crystal adjacent layers by the results of XRD experiments. It can be used as a method to regulate and control the optical properties and pitch of cellulose cholesteric liquid crystals.