Abstract
The dielectric properties of the nematic liquid crystal, 4-4′-n-pentylcyanobiphenyl (K15), and three binary mixtures of K15 with 4-[4′-alkylcyclohexyl]cyanophenyl homologs have been studied. The parallel, perpendicular and isotropic dielectric constants are given as a function of temperature. All measurements were made at 1 KHz. Values of ε⊥ and ε‖, are typically in the range of 7 ± 1 and 17 ± 2, respectively. Temperature ranges from 10°C to TNI + 5°C were explored. The dielectric anisotropy versus T-TNI is also given. 14 > Δε > 7 for pure K15 and all three mixtures when T-TNI < − 1°C. This large dielectric anisotropy is due to the highly polar cyano end group, which has a dipole moment of 4.05 D, and lies along the nematic director for each of these compounds.