Three kinds of isothiocyanate (NCS) liquid crystal materials with biphenyl group were synthesized by coupling reaction
nitration
reduction reaction
etc. The final products were confirmed with IR
NMR spectra. The phase transition temperatures were measured by polarizing microscopy accompanied with a thermal stage and DSC
the results indicated that all of them did not exhibit nematic phase. The Δ
n
of the NCS LC materials detected by ellipsometer via mixed LC materials method was about 0.27
which is higher than other liquid crystal materials with biphenyl group. The response time of the liquid crystal mixture containing NCS material was 20% faster than the original LC material when the concentration of the NCS LC material is 10%. These data indicated that the NCS materials synthesized have high birefringence and fast response properties
and would have some application potential in liquid crystal modulators.
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