Retardation of Molecular Rotations Around the Short Axes at the Transition from the Isotropic to Different Liquid Crystalline Phases

• Autorzy: Urban S. , Gestblom B. , Dąbrowski R.
• Języki publikacji: EN

Abstrakty

EN

Results of the dielectric relaxation studies of several homologous series and some single compounds exhibiting different phase sequences (isotropic - nematic, isotropic - smectic A, C, B and E) are presented. Relaxation times characterizing the molecular rotations around the short axes in the isotropic and a given liquid crystalline (LC) phases were determined. Two quantities, the so-called retardation factor gLC-Is = _LC/_Is and the activation enthalpy are analyzed. In spite of drastic changes of the g-factors in the case of the isotropic - crystal-like smectic phase transitions (Sm B and E) in comparison with the isotropic - liquid-like phases (N, Sm A, Sm C) transitions the activation enthalpy does not depend practically on the LC phase. This will be discussed as resulting from the coupling of the rotational and translational motions.

Słowa kluczowe

EN

liquid crystals; nematics; smectic; dielectric relaxation

• Wydawca: Polskie Towarzystwo Chemiczne
• Czasopismo: Polish Journal of Chemistry
• Rocznik: 2002
• Tom: Vol. 76 / nr 2-3
• Strony: 263--271
• Opis fizyczny: Bibliogr. 19 poz., rys.

Twórcy

autor

Urban S.

• Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow, Poland

autor

Gestblom B.

• Institute of Physics, Uppsala Unwersity, Uppsala, Sweden

autor

Dąbrowski R.

• Institute of Chemistry, Military Technical University, 00-908 Warsaw, Poland

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