Synthsis And Application In Blue Phase Liquid Crystal Of Two Kind Of Azo Materials

In this thesis, a kind of the linear azo compounds and azo compounds with binaphthyl structure were synthesized. The chemical structures of these molecules were confirmed by1H NMR and HRMS spectra. Then the compounds were doped into chiral nematic phase which is composed of nematic liquid crystal and chiral materials. The influence of azo compounds incorporation for blue phase was studied during the heating and cooling process, such as the texture of blue phase, blue phase range and so on. When iquid crystal mixture was maintained at BPI, the influence of azo compounds photoisomerization for blue phase liquid crystal was studied during UV exposure process and recovery process in the dark state. The incorporation of the azo compounds makes crystal domains of blue phase decrease and the influence of blue phase range is concerned with the compounds and the concentration of them. In the aspect of the linear azo compounds, the increase of the concentration enhances the impact of the azo compounds photoisomerization for the blue phase liquid crystal and reduces the exposure time and recovery time. When the azo compound has a large substituent and the substituent can conjugate with benzene ring, the incorporation of the azo compounds have the same effect. Compared with the linear azo compounds, the migration direction of selective reflection wavelength caused by the photoisomerization of azo compounds with binaphthyl structure is opposite.