1 | Author | S. U. Rban, T. Briickert, A. W. Ürflinger | Requires cookie* |
Title | Dielectric Studies on Liquid Crystals under High Pressure: VI. Low Frequency Relaxation Process in the Nematic and Smectic A Phase of 4-n-Octyl-4'-Cyanobiphenyl (8 CB) ![]() | ||
Abstract | Dielectric relaxation studies of 4-n-octyl-4'-cyanobiphenyl (8 CB) were performed in the pressure range 0 .1 -1 2 0 M Pa, the frequency range 1 k H z -1 3 M Hz and the temperature range 2 9 5-331 K. The dielectric behaviour of 8C B in the nematic phase is similar to that of 5CB, 6C B and 7CB. In particular, the activation enthalpy decreases with increasing pressure and the activation volume decreases with increasing temperature in the nematic phase. In the smectic A phase of 8CB both these parameters are markedly lower and show opposite pressure and temperature dependencies. We tentatively interpret these effects as a result of breaking of the dipole-dipole correlations which manifests itself differently in these liquid crystalline phases. | ||
Reference | Z. Naturforsch. 49a, 552 (1994); received March 5 1994 | ||
Published | 1994 | ||
Keywords | Dielectric relaxation, High pressure, Liquid crystals, Activation quantities | ||
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