Behavior of nanoparticle clouds around a magnetized microsphere under magnetic and flow fields / Magnet C.,Kuzhir P.,Bossis G.,Meunier A.,Nave S.,Zubarev A.,Lomenech C.,Bashtovoi V. // PHYSICAL REVIEW E. - 2014. - V. 89, l. 3.

ISSN/EISSN:

2470-0045 / 2470-0053

Type:

Article

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 mu m) 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 alpha >= 2), the Brownian motion seems not to affect the cloud behavior.

Author keywords:

MAGNETORHEOLOGICAL FLUID; COLLOIDAL PARTICLES; SEPARATION; STABILIZATION; FERROFLUIDS; ANISOTROPY; MIXTURES; EQUATION; BUILDUP; CAPTURE

DOI:

10.1103/PhysRevE.89.032310

Web of Science ID:

ISI:000333702800016

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	MAR 31
Publisher	AMER PHYSICAL SOC
Address	ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Language	English
Article-Number	032310
EISSN	2470-0053
Keywords-Plus	MAGNETORHEOLOGICAL FLUID; COLLOIDAL PARTICLES; SEPARATION; STABILIZATION; FERROFLUIDS; ANISOTROPY; MIXTURES; EQUATION; BUILDUP; CAPTURE
Research-Areas	Physics
Web-of-Science-Categories	Physics, Fluids \& Plasmas; Physics, Mathematical
Author-Email	kuzhir@unice.fr
ORCID-Numbers	Kuzhir, Pavel/0000-0001-7089-6197
Funding-Acknowledgement	project ``Factories of the Future{''} {[}260073]; Russian Fund of Fundamental Investigations {[}13-02-91052]; project PICS CNRS/Ural Federal University {[}6102]; Belarusian Republican Foundation for Fundamental Research (exchange of scientists grant)
Funding-Text	This work has been supported by the project ``Factories of the Future{''} (Grant No. 260073, DynExpert FP7), by the Russian Fund of Fundamental Investigations (Grant No. 13-02-91052), by the project PICS 6102 CNRS/Ural Federal University, and by the Belarusian Republican Foundation for Fundamental Research (exchange of scientists grant).
Number-of-Cited-References	54
Usage-Count-Last-180-days	2
Usage-Count-Since-2013	18
Journal-ISO	Phys. Rev. E
Doc-Delivery-Number	AE1CF