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Spatafora-Salazar A, Lobmeyer DM, Cunha LHP, Joshi K, Biswal SL. Hierarchical assemblies of superparamagnetic colloids in time-varying magnetic fields. SOFT MATTER 2021; 17:1120-1155. [PMID: 33492321 DOI: 10.1039/d0sm01878c] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Magnetically-guided colloidal assembly has proven to be a versatile method for building hierarchical particle assemblies. This review describes the dipolar interactions that govern superparamagnetic colloids in time-varying magnetic fields, and how such interactions have guided colloidal assembly into materials with increasing complexity that display novel dynamics. The assembly process is driven by magnetic dipole-dipole interactions, whose strength can be tuned to be attractive or repulsive. Generally, these interactions are directional in static external magnetic fields. More recently, time-varying magnetic fields have been utilized to generate dipolar interactions that vary in both time and space, allowing particle interactions to be tuned from anisotropic to isotropic. These interactions guide the dynamics of hierarchical assemblies of 1-D chains, 2-D networks, and 2-D clusters in both static and time-varying fields. Specifically, unlinked and chemically-linked colloidal chains exhibit complex dynamics, such as fragmentation, buckling, coiling, and wagging phenomena. 2-D networks exhibit controlled porosity and interesting coarsening dynamics. Finally, 2-D clusters have shown to be an ideal model system for exploring phenomena related to statistical thermodynamics. This review provides recent advances in this fast-growing field with a focus on its scientific potential.
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Affiliation(s)
- Aldo Spatafora-Salazar
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Dana M Lobmeyer
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Lucas H P Cunha
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Kedar Joshi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Sibani Lisa Biswal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
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Pei P, Peng Y. The squeeze strengthening effect on the rheological and microstructured behaviors of magnetorheological fluids: a molecular dynamics study. SOFT MATTER 2021; 17:184-200. [PMID: 33332517 DOI: 10.1039/d0sm01149e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Systematic molecular dynamics simulations are conducted on magnetorheological (MR) fluids under steady state, squeeze flows and shear flows. The present study concerns the squeeze-assisted MR fluid strengthening and correlates the suspensions' macroscopic rheological properties to their microstructure evolution in terms of the aggregation kinetics. Simulation results demonstrate that the squeeze strengthening effect on the rheological properties of MR fluids is enhanced with the increasing magnetic field and becomes more prominent for dilute suspensions, but weakened with the increasing squeeze rate after the critical squeeze rate is surpassed. By microscopic inspection, it is found that the rheological properties of MR fluids under squeeze flows are consistent with the microstructured behaviors of MR suspensions in terms of the particle distribution, cluster kinetics, particle connectivity and magnetic energy. This study provides a microstructural insight into the squeeze-assisted MR fluid strengthening, which helps to attain an elegant design of MR devices with high shear performance requirements.
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Affiliation(s)
- Pei Pei
- State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, P. R. China.
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Martínez-Pedrero F, Ortega F, Codina J, Calero C, Rubio RG. Controlled disassembly of colloidal aggregates confined at fluid interfaces using magnetic dipolar interactions. J Colloid Interface Sci 2020; 560:388-397. [DOI: 10.1016/j.jcis.2019.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/03/2019] [Accepted: 10/03/2019] [Indexed: 10/25/2022]
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Darras A, Opsomer E, Vandewalle N, Lumay G. Effect of volume fraction on chains of superparamagnetic colloids at equilibrium. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:123. [PMID: 31512004 DOI: 10.1140/epje/i2019-11883-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 08/05/2019] [Indexed: 06/10/2023]
Abstract
For a few decades, the influence of a magnetic field on the aggregation process of superparamagnetic colloids has been well known on short time scale. However, the accurate study of the equilibrium state is still challenging on some aspects. On the numerical aspect, current simulations have only access to a restricted set of experimental conditions due to the computational cost of long-range interactions in many-body systems. In the present paper, we numerically explore a new range of parameters thanks to sped up numerical simulations validated by a recent experimental and numerical study. We first show that our simulations reproduce results from previous study in well-established conditions. Then we show that unexpectedly long chains are observed for higher volume fractions and intermediate fields. We also present theoretical developments taking into account the interaction between the chains which are able to reproduce the data that we obtained with our simulations. We finally confirm this model thanks to experimental data.
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Affiliation(s)
- A Darras
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium.
- F.R.S.-FRNS, B-1000, Bruxelles, Belgium.
- Experimental Physics, Saarland University, D-66123, Saarbrücken, Germany.
| | - E Opsomer
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium
| | - N Vandewalle
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium
| | - G Lumay
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium
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Robinson DR, Wilson M. Field-induced self-assembly: does size matter? Mol Phys 2018. [DOI: 10.1080/00268976.2018.1481233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- David R. Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Mark Wilson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
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Cheng R, Zhu L, Huang W, Mao L, Zhao Y. Reconfiguring ferromagnetic microrod chains by alternating two orthogonal magnetic fields. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:315101. [PMID: 29947616 DOI: 10.1088/1361-648x/aacf69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
It is well-known that ferromagnetic microrods form linear chains under an external uniform magnetic field B and the chain length is strongly dependent on the applied field, the applied time duration, and the microrod density. When the chains become long enough and the B-field switches to its orthogonal direction, an irreversible morphological transition, i.e. a parallel linear chain array to a 2D network, is observed. The formation of the network depends on the ratio of the average chain length L and separation D, L/D, as well as the magnitude of the changed B-field. When the chain pattern has an L/D larger than a critical value, the network structure will be formed. Such a critical L/D ratio is a monotonic function of B, which determines the bending length of each magnetic chain during the change of B-fields. This morphological change triggered by external magnetic field can be used as scaffolds or building blocks for biological applications or design smart materials.
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Affiliation(s)
- Rui Cheng
- School of Electrical and Computer Engineering, College of Engineering, University of Georgia, Athens, GA 30602, United States of America
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Darras A, Opsomer E, Vandewalle N, Lumay G. Superparamagnetic colloids in viscous fluids. Sci Rep 2017; 7:7778. [PMID: 28798403 PMCID: PMC5552745 DOI: 10.1038/s41598-017-07917-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 06/29/2017] [Indexed: 11/25/2022] Open
Abstract
The influence of a magnetic field on the aggregation process of superparamagnetic colloids has been well known on short time for a few decades. However, the influence of important parameters, such as viscosity of the liquid, has received only little attention. Moreover, the equilibrium state reached after a long time is still challenging on some aspects. Indeed, recent experimental measurements show deviations from pure analytical models in extreme conditions. Furthermore, current simulations would require several years of computing time to reach equilibrium state under those conditions. In the present paper, we show how viscosity influences the characteristic time of the aggregation process, with experimental measurements in agreement with previous theories on transient behaviour. Afterwards, we performed numerical simulations on equivalent systems with lower viscosities. Below a critical value of viscosity, a transition to a new aggregation regime is observed and analysed. We noticed this result can be used to reduce the numerical simulation time from several orders of magnitude, without modifying the intrinsic physical behaviour of the particles. However, it also implies that, for high magnetic fields, granular gases could have a very different behaviour from colloidal liquids.
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Affiliation(s)
- A Darras
- GRASP, CESAM - Physics Department, University of Liège, B-4000, Liège, Belgium.
- F.R.S.-FRNS, B-1000, Bruxelles, Belgium.
- Experimental Physics, Saarland University, D-66123, Saarbrücken, Germany.
| | - E Opsomer
- GRASP, CESAM - Physics Department, University of Liège, B-4000, Liège, Belgium
- Université Paris Diderot, Sorbonne Paris Cité, MSC, CNRS (UMR 7057), F-75013, Paris, France
| | - N Vandewalle
- GRASP, CESAM - Physics Department, University of Liège, B-4000, Liège, Belgium
| | - G Lumay
- GRASP, CESAM - Physics Department, University of Liège, B-4000, Liège, Belgium
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Shahrivar K, Carreón-González E, Morillas JR, de Vicente J. Aggregation kinetics of carbonyl iron based magnetic suspensions in 2D. SOFT MATTER 2017; 13:2677-2685. [PMID: 28332689 DOI: 10.1039/c7sm00075h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the (irreversible) two-dimensional aggregation kinetics of dilute non-Brownian magnetic suspensions in rectangular microchannels using video-microscopy, image analysis and particle-level dynamics simulations. Special emphasis is given to carbonyl iron suspensions that are of interest in the formulation of magnetorheological fluids. The results are compared to non-Brownian suspensions of magnetic latexes. We demonstrate that both suspensions follow a deterministic aggregation process. Furthermore, experimental and simulation aggregation curves can be collapsed onto a master curve when using the appropriate scaling time (∝λ-1ϕ2D-2.5) as a function of only two dimensionless numbers: the lambda ratio (λ) and the particle surface fraction (ϕ2D).
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Affiliation(s)
- Keshvad Shahrivar
- Department of Applied Physics, Faculty of Sciences, University of Granada, C/Fuentenueva s/n, 18071-Granada, Spain.
| | - Elizabeth Carreón-González
- Department of Applied Physics, Faculty of Sciences, University of Granada, C/Fuentenueva s/n, 18071-Granada, Spain.
| | - Jose R Morillas
- Department of Applied Physics, Faculty of Sciences, University of Granada, C/Fuentenueva s/n, 18071-Granada, Spain.
| | - Juan de Vicente
- Department of Applied Physics, Faculty of Sciences, University of Granada, C/Fuentenueva s/n, 18071-Granada, Spain.
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Cheng R, Zhu L, Huang W, Mao L, Zhao Y. Dynamic scaling of ferromagnetic micro-rod clusters under a weak magnetic field. SOFT MATTER 2016; 12:8440-8447. [PMID: 27714351 DOI: 10.1039/c6sm01485b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A controlled configurational change of micro-clusters in suspensions is essential for many smart material applications. In this paper, the dynamic process of ferromagnetic microrod clusters (FMRCs) under an external magnetic field was studied as a function of the cluster size N and the applied field B. The FMRCs rearranged from a side-by-side raft-like structure to an end-to-end chain-like structure, originating from coupled motions through the field-driven alignment of both ferromagnetic microrods and FMRCs. A theoretical model based on an extension of a zig-zag chain was developed, and both the cluster length and orientation could be characterized by a retardation time constant τ, with a relationship τ ∼ N2/B, which agrees well with the experimental results, τ ∼ N2.2±0.2/B0.8±0.1. Such a model can be used to predict other cluster dynamics or the magneto-elastic behavior of other soft matters consisting of FMRCs.
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Affiliation(s)
- Rui Cheng
- College of Engineering, University of Georgia, Athens, Georgia 30602, USA.
| | - Lu Zhu
- College of Engineering, University of Georgia, Athens, Georgia 30602, USA.
| | - Weijie Huang
- Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, USA.
| | - Leidong Mao
- College of Engineering, University of Georgia, Athens, Georgia 30602, USA.
| | - Yiping Zhao
- Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, USA.
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Darras A, Fiscina J, Pakpour M, Vandewalle N, Lumay G. Ribbons of superparamagnetic colloids in magnetic field. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2016; 39:47. [PMID: 27112936 DOI: 10.1140/epje/i2016-16047-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/09/2016] [Indexed: 06/05/2023]
Abstract
While the aggregation process of superparamagnetic colloids in strong magnetic field is well known on short time since a few decades, recent theoretical works predicted an equilibrium state reached after a long time. In the present paper, we present experimental observations of this equilibrium state with a two-dimensional system and we compare our data with the predictions of a pre-existing model. Above a critical aggregation size, a deviation between the model and the experimental data is observed. This deviation is explained by the formation of ribbon-shaped aggregates. The ribbons are formed due to lateral aggregation of chains. An estimation of the magnetic energy for chains and ribbons shows that ribbons are stable structures when the number of magnetic grains is higher than N = 30 .
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Affiliation(s)
- A Darras
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium.
- F.R.S.-FRNS, B-1000, Bruxelles, Belgium.
| | - J Fiscina
- Experimental Physics, Saarland University, D-66123, Saarbrücken, Germany
| | - M Pakpour
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium
| | - N Vandewalle
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium
| | - G Lumay
- GRASP - Physics Department, University of Liège, B-4000, Liège, Belgium
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11
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Reynolds CP, Klop KE, Lavergne FA, Morrow SM, Aarts DGAL, Dullens RPA. Deterministic aggregation kinetics of superparamagnetic colloidal particles. J Chem Phys 2015; 143:214903. [DOI: 10.1063/1.4936323] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Colin P. Reynolds
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Kira E. Klop
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - François A. Lavergne
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Sarah M. Morrow
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Dirk G. A. L. Aarts
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Roel P. A. Dullens
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
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12
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Domínguez-García P. Microrheological consequences of attractive colloid-colloid potentials in a two-dimensional Brownian fluid. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2012; 35:73. [PMID: 22898939 DOI: 10.1140/epje/i2012-12073-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 07/04/2012] [Accepted: 07/10/2012] [Indexed: 06/01/2023]
Abstract
By using microrheological methods commonly employed in videomicroscopy experiments, we study the rheology of a two-dimensional computational fluid formed by Brownian disks with the aim of exploring the influence of some effective colloid-colloid attractive interactions. The model of fluid is developed by Brownian dynamics simulations without hydrodynamical interactions, and it is characterized by calculating its equation of state from the pair distribution function. Micromechanical properties, relative and intrinsic viscosity and freezing are discussed. Then, we include attractive forces such a Asakura-Oosawa depletion force or an empiric expression proposed by Grier and Hal (GH) for an anomalous electrostatic potential observed in confined and charged colloids. By using both potentials, viscosity is clearly increased, but when the GH potential is included, viscoelastic gel state is reached for intermediate values of surface concentration. Finally, we analyse the influence of the attractive potentials in the breaking-up by thermal fluctuations of linear chains formed by 2D particles, finding that the GH potential reduces the characteristical time at which the disks can be considered as disaggregated. In this work, we employ an experimental-like methodology for the study of a Brownian hard-disk fluid, providing a very useful link with experimental procedures.
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Affiliation(s)
- P Domínguez-García
- Dep. Física de Materiales, Universidad Nacional de Educación a Distancia, Madrid, Spain.
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