Haloing in bimodal magnetic colloids: The role of field-induced phase separation / Magnet C.,Kuzhir P.,Bossis G.,Meunier A.,Suloeva L.,Zubarev A. // PHYSICAL REVIEW E. - 2012. - V. 86, l. 1, 1.

ISSN/EISSN:

1539-3755 / 1550-2376

Type:

Article

Abstract:

If a suspension of magnetic micrometer-sized and nanosized particles is subjected to a homogeneous magnetic field, the nanoparticles are attracted to the microparticles and form thick anisotropic halos (clouds) around them. Such clouds can hinder the approach of microparticles and result in effective repulsion between them {[}M. T. Lopez-Lopez, A. Yu. Zubarev, and G. Bossis, Soft Matter 6, 4346 (2010)]. In this paper, we present detailed experimental and theoretical studies of nanoparticle concentration profiles and of the equilibrium shapes of nanoparticle clouds around a single magnetized microsphere, taking into account interactions between nanoparticles. We show that at a strong enough magnetic field, the ensemble of nanoparticles experiences a gas-liquid phase transition such that a dense liquid phase is condensed around the magnetic poles of a microsphere while a dilute gas phase occupies the rest of the suspension volume. Nanoparticle accumulation around a microsphere is governed by two dimensionless parameters-the initial nanoparticle concentration (phi(0)) and the magnetic-to-thermal energy ratio (alpha)-and the three accumulation regimes are mapped onto a alpha-phi(0) phase diagram. Our local thermodynamic equilibrium approach gives a semiquantitative agreement with the experiments on the equilibrium shapes of nanoparticle clouds. The results of this work could be useful for the development of the bimodal magnetorheological fluids and of the magnetic separation technologies used in bioanalysis and water purification systems.

Author keywords:

STRUCTURAL TRANSFORMATIONS; NANOPARTICLES; FERROFLUIDS; PARTICLES; FLUIDS; SUSPENSIONS; CONSTANTS; EMULSIONS; MIXTURES; HGMS

DOI:

10.1103/PhysRevE.86.011404

Web of Science ID:

ISI:000306414700003

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	JUL 13
Publisher	AMER PHYSICAL SOC
Address	ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Language	English
Article-Number	011404
EISSN	1550-2376
Keywords-Plus	STRUCTURAL TRANSFORMATIONS; NANOPARTICLES; FERROFLUIDS; PARTICLES; FLUIDS; SUSPENSIONS; CONSTANTS; EMULSIONS; MIXTURES; HGMS
Research-Areas	Physics
Web-of-Science-Categories	Physics, Fluids \& Plasmas; Physics, Mathematical
ResearcherID-Numbers	Zubarev, Adrey/B-4752-2014
ORCID-Numbers	Kuzhir, Pavel/0000-0001-7089-6197
Funding-Acknowledgement	Biomag (PACA, France); Factories of the Future {[}260073]; CNRS {[}23178]
Funding-Text	We would like to thank Dr. Sebastien Schaub and Yassin Bourras for assistance in experiments, as well as Professor Jacques Persello and Dr. Francoise Giulieri for helpful discussions. Financial support by projects Biomag (PACA, France), ``Factories of the Future{''} (Grant No. 260073, DynExpert FP7), and CNRS ({''}exchange of scientists{''} project No. 23178) is gratefully acknowledged.
Number-of-Cited-References	46
Usage-Count-Since-2013	22
Journal-ISO	Phys. Rev. E
Doc-Delivery-Number	974FD