Dielectric properties of liquid crystals for display and sensor applications

Belyaev, V. V.; Чаусов, Д. Н.; Kurilov, Alexander D.; Rybakov, D. O.; Solomatin, A. S.; Murauski, Anatoli; Muravsky, Alexander; Chigrinov, Vladimir G.; Fan, Fan

doi:10.1002/jsid.352

Cited by 6 publications

(2 citation statements)

References 10 publications

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“…The activation energy values are in the range of (100–120) ± 4 kJ/mol for all of the Ln(III) complexes. They are slightly higher than the values provided for organic nematic liquid crystals − and are comparable to the values obtained for LC polymers . The activation energy calculated for the isotropic phase is significantly lower.…”

Section: Resultssupporting

confidence: 75%

Effect of Magnetic and Electric Field on the Orientation of Rare-Earth-Containing Nematics

et al. 2020

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We report rare-earth-containing metallomesogens with newly synthesized ligands represented by the β-diketone 1-(4-(4-propylcyclohexyl)phenyl)octane-1,3-dione (CPDk 3‑5) and the Lewis base 5,5′-bis(heptadecyl)-2,2′-bipyridine (bpy17‑17). The stoichiometry of the complexes is [Ln(CPDk 3‑5)3bpy17‑17], where Ln is a trivalent rare-earth ion (La, Sm, Eu, Gd, Tb, Dy, Ho, Tm, and Yb). Although the ligands themselves do not form any mesophase, the respective metal complexes produce nematic and smectic A phases. The mesogenic rare-earth complexes were characterized by NMR, MS, POM, DSC, X-ray diffraction, magnetic susceptibility measurements, and dielectric spectroscopy. The metal complexes display a remarkably large magnetic anisotropy in the mesophase. These nematic liquid crystals can, therefore, be easily aligned by an external low-threshold magnetic field.

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Section: Resultssupporting

confidence: 75%

Effect of Magnetic and Electric Field on the Orientation of Rare-Earth-Containing Nematics

et al. 2020

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“…Причем детальное исследование этих характеристик имеет практическое значение и позволяет рекомендовать те или иные мезоморфные функциональные материалы для конкретного применения. Данные о диэлектрической проницаемости и ее зависимости от температуры и состава исследуемой системы необходимы при разработке компонентов для устройств, работа которых основана на электрооптических эффектах [6][7][8][9]. У 4-н-алкилоксибензойных кислот, являющихся одним из компонентов жидкокристаллических материалов, используемых в средствах отображения информации, нематическая мезофаза в большинстве случаев обладает положительной анизотропией диэлектрической проницаемости [10][11][12][13].…”

Section: Introductionunclassified

Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline

Syrbu

Fedorov

Лапыкина

et al. 2021

Fine Chem. Technol.

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Objectives. Our aim was to study the dielectric properties of the 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4’-methylaniline system and reveal how different concentrations of N-(4-n-butyloxybenzylidene)-4’-methylaniline additives affect the dielectric properties of 4-n-pentyloxybenzoic acid.Methods. System properties were investigated using polarization thermomicroscopy and dielcometry.Results. We found that dielectric anisotropy changes its sign from positive to negative at the transition temperature of the high-temperature nematic subphase to the low-temperature one. The anisotropy of the dielectric constant of N-4-n-butoxybenzylidene-4’-methylaniline has a positive value and increases as to the system approaches the crystalline phase. The crystal structure of the 4-n-pentyloxybenzoic acid contains dimers formed by two independent molecules due to a pair of hydrogen bonds. The crystal structure of N-(4-n-butoxybenzylidene)-4’-methylaniline contains associates formed by orientational interactions of two independent molecules. 4-n-Pentyloxybenzoic acid dimers (270 nm) and associates of N-4-n-butoxybenzylidene-4’- methylaniline (250 nm) proved to have approximately the identical length. Considering the close length values of the structural units of both compounds and the dielectric anisotropy sign, we assume that the N-4-n-butoxybenzylidene-4’-methylaniline associates are incorporated into the supramolecular structure of the 4-n-pentyloxybenzoic acid. The specific electrical conductivity of the compounds under study lies between 10−7 and 10−12 S∙cm−1. The relationship between the specific electrical conductivity anisotropy and the system composition in the nematic phase at the identical reduced temperature, obtained between 100 and 1000 Hz is symbatic. However, the electrical conductivity anisotropy values of the system obtained at 1000 Hz are lower compared to those obtained at 100 Hz. At N-(4-n-butoxybenzylidene)-4’-methylaniline concentrations between 30 and 60 mol %, the electrical conductivity anisotropy values are higher than those of the individual component.Conclusions. A change in the sign of the dielectric constant anisotropy of the 4-n-pentyloxybenzoic acid during nematic subphase transitions was established. We showed that the system has the highest dielectric constant anisotropy value when components have an equal number of moles. Highest electrical conductivity anisotropy values are observed when the concentration of the N-4-n-butoxybenzylidene-4᾽-methylaniline system lies between 30 and 60 mol %.

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A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation

Kell

2021

Advances in Microbial Physiology

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Dielectric properties of liquid crystals for display and sensor applications

Cited by 6 publications

References 10 publications

Effect of Magnetic and Electric Field on the Orientation of Rare-Earth-Containing Nematics

Effect of Magnetic and Electric Field on the Orientation of Rare-Earth-Containing Nematics

Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline

A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation

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