Parameters of LC molecules’ movement measured by dielectric spectroscopy in wide temperature range

• Autorzy: Chausov D. N. , Kurilov A. D. , Belyaev V. V. , Kumar S.

Identyfikatory

DOI

10.1016/j.opelre.2017.12.001

• Języki publikacji: EN

Abstrakty

EN

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°C. 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°C 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.

Słowa kluczowe

EN

dielectric relaxation; dielectric spectroscopy; crossover frequency; molecular friction; rotational diffusion; liquid crystals

• Wydawca: Stowarzyszenie Elektryków Polskich ; Polska Akademia Nauk ; Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
• Czasopismo: Opto-Electronics Review
• Rocznik: 2018
• Tom: Vol. 26, No. 1
• Strony: 44--49
• Opis fizyczny: Bibliogr. 45 poz., wykr.

Twórcy

autor

Chausov D. N.

• Moscow Region State University (MRSU), 10a Radio Str., 105005 Moscow, Russia

autor

Kurilov A. D.

• Moscow Region State University (MRSU), 10a Radio Str., 105005 Moscow, Russia
• Moscow Technological University, 78 Vernadskogo Ave., 119454, Moscow, Russia

autor

Belyaev V. V.

• Moscow Region State University (MRSU), 10a Radio Str., 105005 Moscow, Russia
• Peoples’ Friendship University of Russia (RUDN), 6 Miklukho-Maklaya Str., 117198, Moscow, Russia

autor

Kumar S.

• Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Near Mekhri Circle, Bengaluru, Karnataka 560080, India

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Uwagi

Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2018).