Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/102468
Title: Behavior of nanoparticle clouds around a magnetized microsphere under magnetic and flow fields
Authors: Magnet, C.
Kuzhir, P.
Bossis, G.
Meunier, A.
Nave, S.
Zubarev, A.
Lomenech, C.
Bashtovoi, V.
Issue Date: 2014
Publisher: American Physical Society
Citation: Behavior of nanoparticle clouds around a magnetized microsphere under magnetic and flow fields / C. Magnet, P. Kuzhir, G. Bossis, et al. — DOI 10.1103/PhysRevE.89.032310 // Physical Review E - Statistical, Nonlinear, and Soft Matter Physics. — 2014. — Vol. 89. — Iss. 3. — 032310.
Abstract: When a micron-sized magnetizable particle is introduced into a suspension of nanosized magnetic particles, the nanoparticles accumulate around the microparticle and form thick anisotropic clouds extended in the direction of the applied magnetic field. This phenomenon promotes colloidal stabilization of bimodal magnetic suspensions and allows efficient magnetic separation of nanoparticles used in bioanalysis and water purification. In the present work, the size and shape of nanoparticle clouds under the simultaneous action of an external uniform magnetic field and the flow have been studied in detail. In experiments, a dilute suspension of iron oxide nanoclusters (of a mean diameter of 60 nm) was pushed through a thin slit channel with the nickel microspheres (of a mean diameter of 50 μm) attached to the channel wall. The behavior of nanocluster clouds was observed in the steady state using an optical microscope. In the presence of strong enough flow, the size of the clouds monotonically decreases with increasing flow speed in both longitudinal and transverse magnetic fields. This is qualitatively explained by enhancement of hydrodynamic forces washing the nanoclusters away from the clouds. In the longitudinal field, the flow induces asymmetry of the front and the back clouds. To explain the flow and the field effects on the clouds, we have developed a simple model based on the balance of the stresses and particle fluxes on the cloud surface. This model, applied to the case of the magnetic field parallel to the flow, captures reasonably well the flow effect on the size and shape of the cloud and reveals that the only dimensionless parameter governing the cloud size is the ratio of hydrodynamic-to-magnetic forces - the Mason number. At strong magnetic interactions considered in the present work (dipolar coupling parameter α≥2), the Brownian motion seems not to affect the cloud behavior. © 2014 American Physical Society.
Keywords: HYDRODYNAMICS
MAGNETIC FIELDS
MAGNETIC SEPARATION
MICROSPHERES
NANOCLUSTERS
NANOMAGNETICS
NANOPARTICLES
SUSPENSIONS (COMPONENTS)
APPLIED MAGNETIC FIELDS
COLLOIDAL STABILIZATION
DIMENSIONLESS PARAMETERS
MAGNETIC FIELD PARALLEL
MAGNETIC INTERACTIONS
NANO-SIZED MAGNETIC PARTICLES
TRANSVERSE MAGNETIC FIELD
UNIFORM MAGNETIC FIELDS
SUSPENSIONS (FLUIDS)
COLLOID
MAGNETITE NANOPARTICLE
MICROSPHERE
CHEMICAL MODEL
CHEMISTRY
COLLOID
COMPUTER SIMULATION
MAGNETIC FIELD
RADIATION RESPONSE
COLLOIDS
COMPUTER SIMULATION
MAGNETIC FIELDS
MAGNETITE NANOPARTICLES
MICROSPHERES
MODELS, CHEMICAL
URI: http://hdl.handle.net/10995/102468
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 84898987817
PURE ID: 362190
fc0db05a-0958-4075-8e3c-376c23a11036
ISSN: 15393755
DOI: 10.1103/PhysRevE.89.032310
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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