The Synthesis Of Fast Response And High Birefringence Nematic Liquid Crystals

In this paper, we start from the structure of liquid crystal molecules and Systematic study of the different polar substitutes in different position when its viscosity and birefringence on the impact of the LC, center-based group and the flexible side chains on the response speed. We ultimately find a design law of the fast response liquid crystal molecule. On this basis, we design three kinds of the fast response nematic liquid crystal molecules.Three kinds of the fast response nematic liquid crystal molecules which are terminal group with fluorine atoms and NCS and mesogenic group with acetylene group will be synthesized. The synthesis way of the low viscosity and high birefringence is sonogashira coupling reaction. The liquid crystal materials are confirmed with NMR.Finally, the three nematic liquid crystal molecules were tested. Including the polarizing microscope melting point apparatus for LC phase transition point test, mixed with a LC material which birefringence is lager in different concentrations, then test the response time and the birefringence and find the best parameters ratio, and the rotational viscometer for the viscosity of the synthesis nematic LC test. The results show that three kinds of nematic liquid crystal molecules can increase the response speed of liquid crystal. They have a very good value.