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Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid

Magnetic fluid (MF) is a colloidal system consisting of ferromagnetic particles (magnetite) with a diameter of ~10 nm suspended in a dispersion medium of a carrier fluid (for example, kerosene). A distinctive feature of magnetic fluid is the fact that when an electric field is applied to it using tw...

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Autores principales: Chekanov, Vladimir, Kovalenko, Anna
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8836286/
https://www.ncbi.nlm.nih.gov/pubmed/35163564
http://dx.doi.org/10.3390/ijms23031642
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author Chekanov, Vladimir
Kovalenko, Anna
author_facet Chekanov, Vladimir
Kovalenko, Anna
author_sort Chekanov, Vladimir
collection PubMed
description Magnetic fluid (MF) is a colloidal system consisting of ferromagnetic particles (magnetite) with a diameter of ~10 nm suspended in a dispersion medium of a carrier fluid (for example, kerosene). A distinctive feature of magnetic fluid is the fact that when an electric field is applied to it using two electrodes, thin layers consisting of close-packed particles of the dispersed phase are formed in the regions near the surface of both electrodes. These layers significantly affect the macroscopic properties of the colloidal system. In this work, the interpretation of the near-electrode layer is for the first time given as a new type of liquid membrane, in which the particles of the dispersed phase become charged with the opposite sign. On the basis of experimental studies, we propose a physicochemical mechanism of the autowave process in a cell with a magnetic fluid. It is based on the idea of oppositely recharging colloidal particles of magnetite in a liquid membrane. A mathematical model of an autowave process, which is described by a system of coupled partial differential equations of Nernst–Planck–Poisson and Navier–Stokes with appropriate boundary conditions, is proposed for the first time. One-dimensional, two-dimensional, and three-dimensional versions of the model are considered. The dependence of the frequency of concentration fluctuations on the stationary voltage between the electrodes was obtained, and the time of formation of a liquid membrane was estimated. Qualitative agreement between theoretical and experimental results has been established.
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spelling pubmed-88362862022-02-12 Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid Chekanov, Vladimir Kovalenko, Anna Int J Mol Sci Article Magnetic fluid (MF) is a colloidal system consisting of ferromagnetic particles (magnetite) with a diameter of ~10 nm suspended in a dispersion medium of a carrier fluid (for example, kerosene). A distinctive feature of magnetic fluid is the fact that when an electric field is applied to it using two electrodes, thin layers consisting of close-packed particles of the dispersed phase are formed in the regions near the surface of both electrodes. These layers significantly affect the macroscopic properties of the colloidal system. In this work, the interpretation of the near-electrode layer is for the first time given as a new type of liquid membrane, in which the particles of the dispersed phase become charged with the opposite sign. On the basis of experimental studies, we propose a physicochemical mechanism of the autowave process in a cell with a magnetic fluid. It is based on the idea of oppositely recharging colloidal particles of magnetite in a liquid membrane. A mathematical model of an autowave process, which is described by a system of coupled partial differential equations of Nernst–Planck–Poisson and Navier–Stokes with appropriate boundary conditions, is proposed for the first time. One-dimensional, two-dimensional, and three-dimensional versions of the model are considered. The dependence of the frequency of concentration fluctuations on the stationary voltage between the electrodes was obtained, and the time of formation of a liquid membrane was estimated. Qualitative agreement between theoretical and experimental results has been established. MDPI 2022-01-31 /pmc/articles/PMC8836286/ /pubmed/35163564 http://dx.doi.org/10.3390/ijms23031642 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Chekanov, Vladimir
Kovalenko, Anna
Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid
title Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid
title_full Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid
title_fullStr Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid
title_full_unstemmed Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid
title_short Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid
title_sort experimental and theoretical study of an autowave process in a magnetic fluid
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8836286/
https://www.ncbi.nlm.nih.gov/pubmed/35163564
http://dx.doi.org/10.3390/ijms23031642
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