Magnetorheology of magnetic holes compared to magnetic particles

Volkova, Olga; Bossis, Georges; Guyot, M.; Баштовой, В. Г.; Рекс, А. Г.

doi:10.1122/1.551075

Cited by 107 publications

(80 citation statements)

References 9 publications

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“…(17) is observed only for the smallest λ , whereas for larger λ we observe a power law θn ∝ Mn κ with the exponent κ < 1 (plotted in the inset of Figure 10), which decreases with increasing λ . The predicted maximum deviation angle of the critical chain is θmax ≈ 35 ○ (from (17) and (18)). This is not the case in our simulations.…”

Section: Chain Deviationmentioning

confidence: 97%

“…The angle distributions obtained from the simulation data at different shear rates (shown in Figure 9 for λ = 5 and is similar for all calculated λ ) can be partially collapsed onto a single master curve when plotted in the coordinates (n, β θ θn), where β θ is a coefficient, which depends on Mn, as predicted by eq. (17).…”

Section: Chain Deviationmentioning

confidence: 99%

“…The electrical analogs, i.e. ferroelectric suspensions of highly polarizable particles in a nonpolarizable solvent, also display an appreciable enhancement of flow resistance 12 16,17 . The new generation of magnetic colloids based on nanoparticles with accurately tailored size and/or oxide-free magnetic materials feature greatly enhanced interaction strength [18][19][20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

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Self-assembly and rheology of dipolar colloids in simple shear studied using multi-particle collision dynamics

2017

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a Magnetic nanoparticles in a colloidal solution self-assemble in various aligned structures, which has a profound influence on the flow behavior. However, the precise role of the microstructure in the development of the rheological response has not been reliably quantified. We investigate the self-assembly of dipolar colloids in simple shear using hybrid molecular dynamics and multiparticle collision dynamics simulations with explicit coarse-grained hydrodynamics; conduct simulated rheometric studies and apply micromechanical models to produce master curves, showing evidence of the universality of the structural behavior governed by the competition of the bonding (dipolar) and erosive (thermal and/or hydrodynamic) stresses. The simulations display viscosity changes across several orders of magnitude in fair quantitative agreement with various literature sources, substantiating the universality of the approach, which seems to apply generally across vastly different length scales and a broad range of physical systems.

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Section: Chain Deviationmentioning

confidence: 97%

Section: Chain Deviationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Self-assembly and rheology of dipolar colloids in simple shear studied using multi-particle collision dynamics

2017

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“…While experimental results for the field-induced dynamic yield stress have corroborated this linear relationship up to surprisingly high concentrations in both Newtonian and non-Newtonian matrix fluids, a super-linear increase with volume fraction has been observed above about φ CIP = 0.2 (Felt et al 1996;Rankin et al 1999;Chin et al 2001;Volkova et al 2001). This behavior is thought to result from the formation of thick columnar structures, as opposed to the single particle-width chains that dominate at low concentrations.…”

Section: Effect Of Magnetic Particle Concentrationmentioning

confidence: 83%

Magnetorheology in an aging, yield stress matrix fluid

2012

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Field-induced static and dynamic yield stresses are explored for magnetorheological (MR) suspensions in an aging, yield stress matrix fluid composed of an aqueous dispersion of Laponite ® clay. Using a custom-built magnetorheometry fixture, the MR response is studied for magnetic field strengths up to 1 T and magnetic particle concentrations up to 30 v%. The yield stress of the matrix fluid, which serves to inhibit sedimentation of dispersed carbonyl iron magnetic microparticles, is found to have a negligible effect on the field-induced static yield stress for sufficient applied fields, and good agreement is observed between field-induced static and dynamic yield stresses for all but the lowest field strengths and particle concentrations. These results, which generally imply a dominance of inter-particle dipolar interactions over the matrix fluid yield stress, are analyzed by considering a dimensionless magnetic yield parameter that quantifies the balance of stresses on particles. By characterizing the applied magnetic field in terms of the average particle magnetization, a rheological master curve is generated for the fieldinduced static yield stress that indicates a concentration-magnetization superposition. The results presented herein will provide guidance to formulators of MR fluids and designers of MR devices who require a field-induced static yield stress and a dispersion that is essentially indefinitely stable to sedimentation.

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“…The response is maximized for sufficiently high particle concentrations, and this may require solids contents as high as 30% v/v. The typically use of organic media, surface modifier, or nonmagnetic nanoparticles [23][24][25][26][27][28][29] could improve the stability of the fluid but also have the disadvantages of the increased viscosity of the system and thus could hinder the magnetorheological effect. In some cases the organic media have no surface charge and hence there is no electrostatic repulsion between particles, which could prevent their irreversible aggregation induced by van der Waals and magnetic (due to the remnant magnetization) interactions.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Nanoparticles as a Redispersing Additive in Magnetorheological Fluid

Portillo

Iglesias

2017

Journal of Nanomaterials

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Unwanted agglomeration of micro particles in magnetorheological fluid is an important problem for many technological applications. Furthermore, the stability of this kind of fluid is also studied as an important property in many research papers. Prior to use, a redispersion of agglomerated or aggregated (connected by solid phase) particles is often necessary. The objective of this study is to evaluate the dispersibility effect of magnetic nanoparticles as a carrier, while keeping the magnetorheological (MR) effect as high as possible. A simple device based on the estimation of the penetration force of a standard needle is presented. The needle moves across the sample vertically with a constant velocity and it is attached to a scale which registers the force displaced by the needle during the dynamic test. The effect with and without other additives was also studied. Transmission electron microscopy (TEM) and Scanning Electron Microscopy (SEM) reveal a protective behavior of nanoparticles around the micro particles. We conclude that addition of magnetic nanoparticles improves the dispersibility characteristic compared with common dispersing additives without affecting the MR effect.

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Magnetorheology of magnetic holes compared to magnetic particles

Cited by 107 publications

References 9 publications

Self-assembly and rheology of dipolar colloids in simple shear studied using multi-particle collision dynamics

Self-assembly and rheology of dipolar colloids in simple shear studied using multi-particle collision dynamics

Magnetorheology in an aging, yield stress matrix fluid

Magnetic Nanoparticles as a Redispersing Additive in Magnetorheological Fluid

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