Dielectric studies of liquid crystals under high pressure. IV. Static permittivity and low frequency relaxation process in 4-n-hexyl-4′-cyanobiphenyl (6CB)

Abstract

Dielectric studies of 4-n-hexyl-4′-cyanobiphenyl (6CB) were performed in the pressure range 0·1–150 MPa, the frequency range 1 kHz-13 MHz and the temperature range 290–327 K. The temperature and pressure dependencies of the static permittivity ∊0| and the relaxation time τ| are analysed and compared with analogous data obtained recently for 5CB and 6CHBT (parts I-III of this series). It was shown that in the nematic phases of both 4-n-alkyl-4′-cyanobiphenyls the dipole-dipole correlations are broken by relatively low pressure.