Steady state rheological behaviour of multi-component magnetic suspensions Rodríguez Arco, Laura López López, Modesto Torcuato Kuzhir, Pavel García López-Durán, Juan De Dios Rehological baheviors Iron Non-magnetic (PMMA) Magnetic particle 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. 2013-11-29T08:05:19Z 2013-11-29T08:05:19Z 2013 info:eu-repo/semantics/article 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] 1744-683X 1744-6848 doi: 10.1039/c3sm50609f http://hdl.handle.net/10481/29470 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Royal Society of Chemistry