A Comparative Study on the Attributes of Ions in Nematic and Isotropic Phases

概要

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The complex dielectric constant of 4-$n$-pentyl-4′-cyanobiphenyl (5CB) was measured between 0.0001 Hz and 1 kHz in nematic and isotropic phases. Dielectric relaxation due to space-charge polarization was observed for both phases. In the nematic phase, the diffusion coefficient $D_{\perp}$ and the mobility $\mu_{\perp}$ of ions in 5CB were determined by theoretical analysis for the frequency dependence of the complex dielectric constant. The mobility $\mu_{\parallel}$ was estimated by an extrapolation procedure utilizing a magnetic field. The activation energies for $\mu_{\perp}$ and $\mu_{\parallel}$ were calculated in accordance with the Arrhenius plots; furthermore, the relationship between the mobility and the viscosity coefficients of 5CB was investigated. The Miesowicz viscosity coefficients $\eta_{1}$, $\eta_{2}$ and $\eta_{3}$ were considered in the nematic phase, and it was found that the product value of $\mu_{\perp}$ and $\eta_{3}$ is almost the same as that of $\mu_{\parallel}$ and $\eta_{2}$ but smaller than the value obtained in the isotropic phase.
Publication Office, Japanese Journal of Applied Physics, Faculty of Science, University of Tokyoの論文
2001-01-15