Dielectric and Optical Studies of Homologous Series of Bicyclo[2,2,2]octane Derivatives with -NCS Terminal Group

Herba, H.; Z̊ywucki, B.; Czechowski, G.; Bauman, Danuta; A, Wasik; Jadżyn, Jan

doi:10.12693/aphyspola.87.985

Cited by 9 publications

(2 citation statements)

References 16 publications

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“…This difference is attributed to the antiparallel alignment of the molecules with the strong dipole moment in the nematic phase [9,10]. Such association was also previously found for other liquid crystals with -NCS end group [11][12][13] and liquid crystals with -CN group [10,11,14,15]. The relaxation strength decreases with increase of the temperature, and simultaneously the relaxation frequency, corresponding to the maximum of the absorption spectrum, shifts towards higher frequencies.…”

Section: Methodssupporting

confidence: 71%

Dielectric Behaviour of 1-(4-Isothiocyanatophenyl)-2-(4-hexyl- bicyclo[2,2,2]octane-1)ethane in Nematic and Isotropic Phases

Jadżyn

Legrand

Kędziora

et al. 1996

Zeitschrift Für Naturforschung A

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Static and dynamic investigations of the dielectric properties of the liquid crystal l-(4-isothiocyanatophenyl)-2-(4-hexyl-bicyclo[2,2,2]octane-l)ethane in the nematic and isotropic phases have been carried out in the frequency region from 1 kHz to 1 GHz. Two relaxation processes, described by the Debye functions, have been observed not only in the isotropic but also in the nematic phase, when the measurements of the electric permittivity vs. frequency have been made parallel to the orientation axis of liquid crystal. These processes are related to the rotation of the permanent dipole moment around two main molecular axes. The height of the potential barrier which hinders the rotation of the liquid crystal molecule around the short axis in the ordered nematic phase and the order parameter of the liquid crystal investigated have been estimated on the basis of the relaxation time values in the nematic and isotropic phases.

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Section: Methodssupporting

confidence: 71%

Dielectric Behaviour of 1-(4-Isothiocyanatophenyl)-2-(4-hexyl- bicyclo[2,2,2]octane-1)ethane in Nematic and Isotropic Phases

Jadżyn

Legrand

Kędziora

et al. 1996

Zeitschrift Für Naturforschung A

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“…Such values of S obtained for the nTPEB series are significantly higher than those predicted by the Maier-Saupe theory [25] (Fig. 4) and those determined for many other liquid crystals [17,21,22,[26][27][28][29][30][31]. This effect can be connected with the length of nTPEB molecules (they have three benzene rings, whereas other liquid crystals investigated possess only two aromatic rings) and/or with the occurrence of the very highly ordered smectic B phase.…”

Section: Order Parameter Of the Dye-liquid Crystal Mixturesmentioning

confidence: 73%

Study of Azo Dye-n TPEB Mixtures in the Nematic and Smectic B Phases by Means of Polarized Light Absorption

Bauman

Chrzumnicka

Dąbrowskia

1998

Zeitschrift Für Naturforschung A

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The influence of the dichroic azo dye on the phase transition temperatures of the mesogenic homolo-gous series of 1-[4-n-alkyl-biphenyl]-2-[4-isothio-cyanatophenyl] ethane (nTPEB) for n = 2 -10 has been examined. For the dye-nTPEB mixtures the polarized absorption spectra as a function of tem-perature have been recorded. From these spectra the order parameter of the dye dissolved in the liquid crystalline hosts in the whole region of the nematic phase has been determined. The order parameter has revealed the odd-even alternation, similarly as the clearing temperature. In the smectic B phase the mosaic texture has been observed and conclusions concerning structural form of this phase have been drawn.

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1.02:9 - 494

Pestov¹

2003

Subvolume A

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Dielectric and Optical Studies of Homologous Series of Bicyclo[2,2,2]octane Derivatives with -NCS Terminal Group

Cited by 9 publications

References 16 publications

Dielectric Behaviour of 1-(4-Isothiocyanatophenyl)-2-(4-hexyl- bicyclo[2,2,2]octane-1)ethane in Nematic and Isotropic Phases

Dielectric Behaviour of 1-(4-Isothiocyanatophenyl)-2-(4-hexyl- bicyclo[2,2,2]octane-1)ethane in Nematic and Isotropic Phases

Study of Azo Dye-n TPEB Mixtures in the Nematic and Smectic B Phases by Means of Polarized Light Absorption

1.02:9 - 494

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