Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline
https://doi.org/10.32362/2410-6593-2021-16-2-138-147
Abstract
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 %.
Keywords
About the Authors
S. A. SyrbuRussian Federation
Dr. Sci. (Chem.), Professor, Deputy Head for the Development of Extra-budgetary Activities,
33, Stroitelei pr., Ivanovo, 153040
M. S. Fedorov
Russian Federation
Cand. Sci. (Chem.), Associate Professor, Department of Fundamental and Applied Chemistry,
39, Ermaka ul., Ivanovo, 153025
E. A. Lapykina
Russian Federation
Cand. Sci. (Chem.), Associate Professor, Department of Fundamental and Applied Chemistry,
39, Ermaka ul., Ivanovo, 153025
V. V. Novikov
Russian Federation
Cand. Sci. (Eng.), Associate Professor, Department of Fundamental Physics and Nanotechnology,
39, Ermaka ul., Ivanovo, 153025
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Supplementary files
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1. Fig. 3. The crystal packing fragment of 4-n-pentyloxybenzoic acid molecules (the molecule long axes are in the plane of the figure). | |
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2. This is to certify that the paper titled Dielectric properties of the system: 4-n-pentyloxybenzoic acid–N-(4-nbutyloxybenzylidene)-4'-methylaniline commissioned to us by Svetlana A. Syrbu, Mikhail S. Fedorov, Elena A. Lapykina, Victor V. Novikov has been edited for English language and spelling by Enago, an editing brand of Crimson Interactive Inc. | |
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- The crystal structure of N-(4-n-butoxybenzylidene)-4'-methylaniline contains associates formed by orientational interactions between two independent molecules. Close length values of 4-n-pentyloxybenzoic acid dimers (270 nm) and associates of N-(4-n-butoxybenzylidene)-4'-methylaniline (250 nm) were noted.
- The dielectric constant anisotropy of the of 4-n-pentyloxybenzoic acid changes its sign from positive to negative at the transition temperature of the high-temperature nematic subphase to the low-temperature nematic subphase.
- The highest values of the electrical conductivity anisotropy are observed when the system content ranges between 30 and 60 mol % N-(4-n-butoxybenzylidene)-4'-methylaniline.
Review
For citations:
Syrbu S.A., Fedorov M.S., Lapykina E.A., Novikov V.V. Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline. Fine Chemical Technologies. 2021;16(2):138-147. https://doi.org/10.32362/2410-6593-2021-16-2-138-147