Abstract
Viscosity η 2 and longitudinal relaxation time τ|| of the nematogenic members of the n-alkyl-cyclohexyl-cyanophenyl (nPCH) series, studied under elevated pressure some time ago, are re-analysed using the scaling law TVγ proposed originally for structural relaxation times in glass-forming liquids. The data obtained at isobaric, isothermal and isochoric thermodynamic conditions could be scaled to master curves with one adjustable parameter γ characterising a steepness of the intermolecular potential. These parameters, γη, γτ and Γ (obtained from the respective analyses of the T–V dependences along the clearing line) are compared and discussed. In spite of the fact that the two examined dynamical quantities, viscosity and relaxation time, characterise different aspects of the dynamic behaviour of molecules within the nematic phase, a good consistency of the potential parameters was achieved, especially when reduced quantities were analysed.
Acknowledgement
The author thanks C.M. Roland for useful suggestions.