Study of molecular dynamics in nematic and isotropic phases of 4-isothiocyanatophenyl 4-hexyl-bicyclo[2,2,2]octane-1carboxylate by dielectric spectroscopy

Jadżyn, Jan; Legrand, Christian; Kędziora, P.; Bauman, Danuta

doi:10.1016/s0022-2860(96)09620-2

“…The nematic potential causes the long-range orientational order and hinders the rotation of the molecules around the short axis, so the corresponding relaxation time is significantly longer than that in the isotropic phase. This fact allows one to determine the height of the nematic potential barrier and thus the orientational order parameter from the dielectric data [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics of 4-(trans-4'-n-Heptylcyclohexyl)- Isothiocyanatobenzene Studied with Dielectric Relaxation Spectroscopy

Bauman

¹

,

Czechowski

²

,

Jadżyn

³

et al. 2000

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Dielectric relaxation study was carried out for the nematic and isotropic phases of 4-(trans-4'-n-heptylcyclohexyl)isothiocyanatobenzene in the frequency range from 100 kHz to 1 GHz. In the nematic phase two relaxation processes were recorded for the electric permittivity component measured parallel to the molecular orientation (director n) and three relaxation processes -for the perpendicular permittivity component. The strength of the nematic potential and the nematic order parameter were estimated.

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“…4 This value is in good agreement with the Maier-Saupe theory, 34 and experimental results for some low molecular mass liquid crystals. 35,36 Thus, the diminishing of the frequency of maximum dielectric loss with respect to the values found for low molecular mass liquid crystals, 31,37,38 both for dye and mesogenic groups relaxations, is not related with the height of the nematic potential barrier. In general, the relaxation frequency also depends on the viscosity of the substance.…”

Section: Dielectric Relaxationmentioning

confidence: 83%

“…This effect is typical for low molecular mass mesogens. 31,37,38 The amplitude and the width of the dye relaxation band depend not only on the temperature but also on the concentration of the dye. On the other hand, these parameters are practically independent on the terminal group (hydrogen atom or benzene ring).…”

Section: Dielectric Relaxationmentioning

confidence: 99%

Thermal and dielectric properties of oriented liquid crystalline polysiloxane doped with azo-dye

Wolarz

¹

,

Kilian

²

,

Haase

³

et al. 1999

J. Polym. Sci. B Polym. Phys.

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4

0

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Investigations of dielectric relaxation and thermal properties of mixtures composed of liquid crystalline side‐chain polysiloxane and low molecular mass azo‐dye have been carried out. The dyes have been chosen to solublize well in the polymer matrix at concentrations up to 0.08 mol fraction. The dielectric relaxation experiments have shown the presence of separate processes attributed to reorientational motions of mesogenic side groups and dye molecules. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 369–377, 1999

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“…4 This value is in good agreement with the Maier-Saupe theory, 34 and experimental results for some low molecular mass liquid crystals. 35,36 Thus, the diminishing of the frequency of maximum dielectric loss with respect to the values found for low molecular mass liquid crystals, 31,37,38 both for dye and mesogenic groups relaxations, is not related with the height of the nematic potential barrier. In general, the relaxation frequency also depends on the viscosity of the substance.…”

Section: Dielectric Relaxationmentioning

confidence: 88%

“…This effect is typical for low molecular mass mesogens. 31,37,38 The amplitude and the width of the dye relaxation band depend not only on the temperature but also on the concentration of the dye. On the other hand, these parameters are practically independent on the terminal group (hydrogen atom or benzene ring).…”

Section: Dielectric Relaxationmentioning

confidence: 99%

Thermal and dielectric properties of oriented liquid crystalline polysiloxane doped with azo‐dye

Wolarz

¹

,

Kilian

²

,

Haase

³

et al. 1999

J. Polym. Sci. B Polym. Phys.

Self Cite

View full text Add to dashboard Cite

Investigations of dielectric relaxation and thermal properties of mixtures composed of liquid crystalline side-chain polysiloxane and low molecular mass azo-dye have been carried out. The dyes have been chosen to solublize well in the polymer matrix at concentrations up to 0.08 mol fraction. The dielectric relaxation experiments have shown the presence of separate processes attributed to reorientational motions of mesogenic side groups and dye molecules.

show abstract

Study of molecular dynamics in nematic and isotropic phases of 4-isothiocyanatophenyl 4-hexyl-bicyclo[2,2,2]octane-1carboxylate by dielectric spectroscopy

Cited by 8 publications

References 8 publications

Molecular Dynamics of 4-(trans-4'-n-Heptylcyclohexyl)- Isothiocyanatobenzene Studied with Dielectric Relaxation Spectroscopy

Molecular Dynamics of 4-(trans-4'-n-Heptylcyclohexyl)- Isothiocyanatobenzene Studied with Dielectric Relaxation Spectroscopy

Thermal and dielectric properties of oriented liquid crystalline polysiloxane doped with azo-dye

Thermal and dielectric properties of oriented liquid crystalline polysiloxane doped with azo‐dye

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