Synthesis Of Novel Low Molar Mass Thermotropic Liquid Crystals And Their Mesomorphism

As environmentally friendly materials, liquid crystals have attracted great attention of researchers due to their ubiquitous commercial applications in flat panel display. In order to satisfy the new needs, it is an important work to synthesize new liquid crystalline materials and study the structure-property relationship of these molecules. In this thesis, a type of biphenyl rod-like liquid crystals and two types of triphenylene discotic liquid crystals were synthesized. The purity and structure characterization of these compounds were carried out with 1H NMR. Thermal gravimetry analysis (TGA) showed these compounds have good thermal stability. The thermotropic liquid crystal properties were studied through polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The structure-property relationship of these compounds was discussed. The experimental work of this thesis consists following three parts:1. Three series of compounds with different rigid core length, H2n+1Cn-OC6H4-C6H4-OCH2-C6H4-CO2-CmH2m+1 (series A, n = 8, 12, 16; m = 6, 12, 14, 16), H2m+1Cm-O2C- C6H4-CH2O-C6H4C6H4-OCH2-C6H4-CO2-CmH2m+1 (series B, m = 6, 12, 14, 16), H2m+1Cm-O2C-C6H4-CH2O-C6H4-OCH2-C6H4-CO2-CmH2m+1 (series C, m = 6,12,14,16) were synthesized. The POM and DSC results show that except for compound C-16, other compounds display liquid crystalline properties. And liquid crystalline properties depend on molecular symmetry, length of rigid...