Synthesis and high frequency dielectric properties of low melting point triphenyl dialkyne liquid crystals

The liquid crystal materials used for liquid crystal microwave communication devices are composed of high birefringence liquid crystal compounds, most of which have higher melting points, making the liquid crystal compositions have higher low temperature eutectic points, unfavorable for the development of microwave communication devices. In this paper, eight kinds of fluorinated ethyl triphenyldialkyne liquid crystal compounds were designed and synthesized, and configured them in a certain ratio to form a liquid crystal composition MA with a low-temperature co-melting point around -46 degrees C. And we mixed them with several other liquid crystals and tested the dielectric properties of the liquid crystal compositions in the microwave frequency band (11 similar to 35 GHz) using the rectangular resonant cavity perturbation method, and obtained a dielectric constant value (Delta epsilon(r)) of 0. 954 at 18 GHz, the maximum dielectric loss is (tan delta epsilon(rmax)) 0.008 6, which meets the performance requirements of low melting point liquid crystal materials for microwave applications.