Thermodiffusion anisotropy under a magnetic field in ionic liquid-based ferrofluids
| Autor: | Fabrice Cousin, J. C. Riedl, Mitradeep Sarkar, Emmanuelle Dubois, T. Fiuza, G. Demouchy, Régine Perzynski, Jerome Depeyrot, Andrejs Cēbers, F. Gélébart, Guillaume Mériguet, Véronique Peyre |
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| Přispěvatelé: | PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidade de Brasilia [Brasília] (UnB), University of Latvia (LU), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université de Cergy Pontoise (UCP), Université Paris-Seine, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2021 |
| Předmět: |
[PHYS]Physics [physics]
Ferrofluid Materials science Condensed matter physics 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Magnetic field chemistry.chemical_compound Dipole chemistry Virial coefficient Ionic liquid Bistriflimide Small-angle scattering 0210 nano-technology Anisotropy |
| Zdroj: | Soft Matter Soft Matter, Royal Society of Chemistry, 2021, 17 (17), pp.4566-4577. ⟨10.1039/d0sm02190c⟩ Soft Matter, 2021, 17 (17), pp.4566-4577. ⟨10.1039/d0sm02190c⟩ |
| ISSN: | 1744-683X 1744-6848 |
| DOI: | 10.1039/d0sm02190c |
| Popis: | International audience; Ferrofluids based on maghemite nanoparticles (NPs), typically 10 nm in diameter, are dispersed in an ionic liquid (1-ethyl 3-methylimidazolium bistriflimide - EMIM-TFSI). The average interparticle interaction is found to be repulsive by small angle scattering of X-rays and of neutrons, with a second virial coefficient A2 = 7.3. A moderately concentrated sample at Φ = 5.95 vol% is probed by forced Rayleigh scattering under an applied magnetic field (up to H = 100 kA m-1) from room temperature up to T = 460 K. Irrespective of the values of H and T, the NPs in this study are always found to migrate towards the cold region. The in-field anisotropy of the mass diffusion coefficient Dm and that of the (always positive) Soret coefficient ST are well described by the presented model in the whole range of H and T. The main origin of anisotropy is the spatial inhomogeneities of concentration in the ferrofluid along the direction of the applied field. Since this effect originates from the magnetic dipolar interparticle interaction, the anisotropy of thermodiffusion progressively vanishes when temperature and thermal motion increase. |
| Databáze: | OpenAIRE |
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