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Title: | Parameters of LC molecules’ movement measured by dielectric spectroscopy in wide temperature range |
Authors: | Chausov, D N Kurilova, A D Belyaev, V.V. Kumar, Sandeep |
Keywords: | Dielectric relaxation Dielectric spectroscopy Crossover frequency Molecular friction Rotational diffusion Liquid crystals |
Issue Date: | 2-Mar-2018 |
Publisher: | Elsevier B. V. |
Citation: | Opto-Electronics Review, 2018, Vol.26, p44-49 |
Abstract: | Dielectric properties of a nematic liquid crystal (NLC) mixture ZhK-1282 were investigated in the frequency range of 102–106Hz and a temperature range of −20 to 80 °С. On the basis of the Debye’s relaxation polarization model dielectric spectra of temperature dependence of the orientational relaxation time τ and the dielectric strength δe were numerically approximated at the parallel orientation of a molecular director relative to alternating electric field. Influence of ester components in the mixture plays crucial role in relaxation processes at low temperature and external field frequency. The activation energy of the relaxation process of a rotation of molecules around their short axis was measured in a temperature interval of −20 to +15 °С in which the dispersion of a longitudinal component of the dielectric constant takes place. The energy of potential barrier for polar molecules rotation in the mesophase was calculated. The value of the transition entropy from the nematic to isotropic phase was obtained from this calculation. The values of the coefficient of molecular friction and rotational diffusion were obtained by different methods. The experimental data obtained are in a satisfactory agreement with the existing theoretical models. |
Description: | Restricted Access. |
URI: | http://hdl.handle.net/2289/6887 |
ISSN: | 1230-3402 |
Alternative Location: | http://arxiv.org/abs/cond-mat/ https://doi.org/10.1016/j.opelre.2017.12.001 |
Copyright: | 2018 Elsevier Inc. |
Appears in Collections: | Research Papers (SCM) |
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2018_Opto-Electronics Review_V26_p44-49.pdf Restricted Access | Restricted Access | 1.16 MB | Adobe PDF | View/Open Request a copy |
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