High pressure studies of the static permittivity tensor components in the nematic phase of 6CB

The dielectric permittivity tensor components, epsilon(II) and epsilon(perpendicular to), in the nematic phase of 6CB (4-n-hexyl-4'- cyanobiphenyl) were measured in the pressure range 0.1 - 130MPa and the temperature range 12 - 58 degrees C. The dielectric anisotropy, Delta epsilon(p, V, T) = epsilon(II) - epsilon(perpendicular to), was analysed in isothermal, isobaric and isochoric conditions taking into account the pVT data and the well known Maier and Meier equation. On that basis the nematic order parameter S(p, V, T) was determined. This was used to calculate the parameter c relating the interaction potential with the volume (density). Its value gamma = 4.1 agrees very well with other estimates.