Temperature characteristic of permittivity and splay elastic constant for fluorinated liquid crystal mixtures

摘要

This paper describes an experimental investigation for physical properties of fluorinated phenyl bicyclohexane liquid crystals (LCs) mixtures. Measurements are reported of the large anisotropic dielectric properties of two structurally similar LCs (1,2-difluoro-4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl] benzene and 1-cyano-2-fluoro-4-[trans-4-(trans-4-propylcyclohexyl) cyclohexyl] benzene) mixed with a zero dielectric anisotropic LC (1-methyl-2-fluoro-4- [trans-4-(trans-4-ethylcyclohexyl) cyclohexyl] benzene). The results indicate that the mixing proportions strongly influence the dielectric constants along with the longer molecular axis. For two samples which is made from meta-para- or meta-fluorine substituted molecules, the temperature dependence of the anisotropic dielectric striking resemble that of a unitary compound with para-fluorine substituted. The threshold voltage of the mixtures relies on the element that possesses a large dielectric anisotropic. The mixing of the materials leads to a slight increase for splay elastic constants in an anti-parallel measurement cell.