Synthesis And Study On The Properties Of Chiral LCs And LCD Chiral Dopant

Based on the liquid crystal molecules theory, two kinds of chiral liquid crystal compounds were synthesized by choosing p-bromophenol,trans-n-alkylcyclohexane Bromide,(-)-2-methyulbutanol,methyl p-hydroxylbenzoate as primary materials through the reactions of coupling,etherification,esterification et al; An important chiral dopant S811 was synthesized by choosing (-)-2-octanol as chiral group. Mixture was made of the dopant and wide-temperature range TN mixed liquidcrystals: studied the dependence of electro-optical properties of TN mixed liquidcrystals on capacitance of chiral dopant.The structure of intermediates and terminal materials was identified by Meltingpoint,FTIR,~1HNMR et al. The purity of two kinds ofchiral liquid crystal compounds was detected by HPLC; their properties of liquid crystal crystalline were characterized by Differential Scanning Calorimeter(DSC),Thermal Polarized Optical Microscope(TPOM) and X-ray Diffraction(XRD). The Instrument of Determining Comprehensive Parameters LCD-5016C studied the electro-optical properties of the mixture.The main points of this dissertion consist the following points:1. Basic theory and application prospects of ferroelectric liquid crystal and cholesteric liquid crystal were summarized, according to Ferroelectric liquid crystal molecular structure theory, two kinds of ester liquid crystal coumpounds were designed and synthesized by choosing (-)-2-methyulbutanol as chiral center. Some of the more common routes of esterification were compared, the experimental factors were discussed, and optimal synthetic route was selected.2. The liquid crystalline properties of two chiral liquid crystal compounds Were characterized by using DSC,TPOM,XRD. The length of molecule was analog by using Chem.3D MM2 template when it was at the lowest energy chain with optimal conformation. And reasonable explanation of the liquid crystal phase was given according to the X-ray diffraction results.3. Adopted a more suitable routes in the synthesis of LCD chiral dopant S811, the DCC/DMAP catalytic esterification method was conducted a study and discussion.4. Mixture was made of the dopant and wide-temperature range TN mixed liquidcrystals, the dependence of electro-optical properties such as threshold voltage,threshold steep,rise time,fall time,contrast,viewing angle of TN mixed liquidcrystals on capacitance of chiral dopant was studied.