The Synthesis And Mesomorphic Properties Of New Flourinated Liquid Crystals

In this thesis, four kinds of fluorinated liquid crystal compounds were designed and synthesized. Their mesomorphic properties were studied by differential scanning calorimetry and polarized optical microscope. We concluded three points:a. The clearing point decrease as the terminal alkyl chain is lengthened.b. The terminal group and the center bridge have a great influence on the performance of liquid crystals.The alkoxy group has more advantages than alkyl group;As for the center bridge, compounds with acetylenic linkage have higher clearing point and wider transition temperature ranges than those with ester group and benzyloxy group.c. The compounds with two acetylenic bonds have higher clearing points and high birefringence which have great application prospect.Most of the compounds are nematic liquid crystals, but some compounds have smectic phase as the terminal alkyl chain is lengthened. Most of these target compounds have potential application value.