Dielectric relaxation in nematic cyclohexane derivatives

ABSTRACT Dielectric properties of a new class of liquid crystals were investigated in nematic and isotropic phases. The measurements, in microwave frequency region, of the complex permittivity were performed on oriented samples of two compounds: p-heptyl-p′-cyanophenyl cyclohexane and p-heptyl-p′-cyanocyclohexyl cyclohexane. The Cole-Cole plots are presented at different temperatures and compared with those of the analogous p-heptyl-p′-cyanobiphenyl, previously reported. The effects of substitution of a phenyl ring by a saturated cyclic ring on dielectric relaxation mecanisms are discussed.