Synthsis And Application In Optically Isotropic Liquid Crystals Of Two Kinds Of Aromatic Azo Compounds

In this thesis, two kinds of azo compounds with high dichroism and linear azo compounds were synthesized. The synthetic process of these molecules involved the etherification of phenol, the reduction of the nitro group, the diazotization of the aromatic amine in acid and alkaline condition. By improving the conventional synthetic processes, simpler experimental conditions and higher yields were gotten. The azo compounds with large dichroism were doped into optically isotropic chiral liquid crystals, polarization-independent electro-optical materials with wide phase temperature range, fast renponse time and large Kerr constant based on dichroic-dye-doped polymer stabilized optically isotropic chiral liquid crystals were prepared. These materials also show large contrast ratio, which are three times larger than the report’s before. Besides, we discussed why these materials show excellent electro-optical performances from the perspective of the molecular structure and theoretical calculation. Then the linear azo compounds were doped into blue phase, the influence of the azo compounds on blue phase was investigated, such as solubility, texture of blue phase, optical tuning characteristics and so on. With the increasing of UV exposure time and azo compounds concentration, the influence of azo compounds photoisomerization on blue phase was more obviously. From the view of molecular structure, when the azo compound has a large molecular structure and rigid core, the optical tuning characteristic is better.