ASYMMETRICAL NONPOLAR DIPHENYL-DIACETYLENE LIQUID CRYSTALS AND EUTECTIC MIXTURES

摘要

A new class of asymmetrical diphenyl-diacetylene liquid crystal compounds exhibit ideal properties for formulating eutectic mixtures suitable for infrared and microwave applications. The new class of liquid crystal compounds comprise asymmetrical nonpolar end groups. These compounds exhibit low melting points, wide nematic temperature range and low heat fusion enthalpy. Eutectic mixtures containing entirely diphenyl-diacetylene homologs using the new compounds have high birefringence, low viscosity and wide nematic range. These unique properties are especially advantageous when these mixtures are used in infrared spatial light modulators, high speed liquid crystal modulators and polymer dispersed liquid crystals shutters. The new asymmetrical diphenyl-diacetylene liquid crystal compounds comprise the following basic structure: R1-C6H4-C=C-C=C-C6H4-R2 wherein R1 and R2 are nonpolar end groups and R1 does not equal R2. R1 is selected from the group consisting of alkyl, alkoxy, alkenyl and alkenyloxy end groups and R2 is selected from the group consisting of alkyl, alkenyl and alkenyloxy. In another embodiment, the liquid crystal compound can comprise an alkenyl group having the general formula: CxH2x+1CH=CH-(CH2)n-2-x in either the R1 or R2 location. Moreover, the liquid crystal compound can comprise such an alkenyl group in both R1 and R2 locations, so long as R1 does not equal R2. Eutectic mixtures for infrared and microwave applications comprise at least one asymmetrical nonpolar diphenyl diacetylene liquid crystal compound having the general structures described above.