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Please use this identifier to cite or link to this item: http://hdl.handle.net/10481/29470

Title: Steady state rheological behaviour of multi-component magnetic suspensions
Authors: Rodríguez-Arco, Laura
López-López, Modesto T.
Kuzhir, Pavel
García López-Durán, Juan de Dios
Issue Date: 2013
Abstract: In this paper, we study the rheological behaviour (in the absence of a magnetic field and upon its application) of multi-component magnetic suspensions that consist of a mixture of magnetic (iron) and non-magnetic (PMMA) particles dispersed in a liquid carrier. These suspensions exhibit considerably higher viscosity and yield stress in the absence of a magnetic field than single-component suspensions of the same solid fraction, as a consequence of the adsorption of the iron particles on the PMMA ones. The adsorbed layer of iron particles on the PMMA ones is observed through optical microscopy of dilute samples and confirmed by attenuated total reflectance. Microscopic observations also show that the resulting non-magnetic-core–magnetic-shell composites move upon magnetic field application and aggregate into particle structures aligned with the applied field. These structures, which consist of both types of particles, give rise to high values of the static and dynamic yield stresses upon field application. Actually, both quantities are much higher than those of a suspension with the same volume fraction of magnetic particles, and increase when the amount of non-magnetic ones increases. These trends are adequately predicted by a theoretical model that considers that the main contribution to the yield stress is the change of the suspension magnetic permeability when particle chains are deformed by the shear.
Sponsorship: This work was supported by Projects P08-FQM-3993, P09-FQM-4787 (Junta de Andalucía, Spain) and FIS2009-07321 (MICINN, Spain). In addition, L. Rodríguez-Arco and M.T. López-López acknowledge financial support by Secretaría de Estado de Educación, Formación Profesional y Universidades (MECD, Spain) through its FPU program and the University of Granada (Spain), respectively.
Publisher: Royal Society of Chemistry
Keywords: Rehological baheviors
Iron
Non-magnetic (PMMA)
Magnetic particle
URI: http://hdl.handle.net/10481/29470
ISSN: 1744-683X
1744-6848
Rights : Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License
Citation: Rodríguez-Arco, L.; et al. Steady state rheological behaviour of multi-component magnetic suspensions. Soft Matter, 9: 5726-5737 (2013). [http://hdl.handle.net/10481/29470]
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