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Kuznetsov AA, Kantorovich SS. Magnetostatic response and field-controlled haloing in binary superparamagnetic mixtures. Phys Rev E 2023; 108:064603. [PMID: 38243475 DOI: 10.1103/physreve.108.064603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 11/16/2023] [Indexed: 01/21/2024]
Abstract
Nowadays, magnetoresponsive soft materials, based not simply on magnetic nanoparticles but rather on multiple components with distinct sizes and magnetic properties in both liquid and polymeric carriers, are becoming more and more widespread due to their unique and versatile macroscopic response to an applied magnetic field. The variability of the latter is related to a complex interplay of the magnetic interactions in a highly nonuniform internal field caused by spatial inhomogeneity in multicomponent systems. In this work, we present a combined analytical and simulation study of binary superparamagnetic systems containing nanoclusters and dispersed single-domain nanoparticles in both liquid and solid carrier matrices. We investigate the equilibrium magnetic response of these systems for wide ranges of concentrations and interaction energies. It turns out that, while the magnetization of a binary solid can be both above and below that of an ideal superparamagnetic gas, depending on the concentration of the dispersed phase and the interparticle interactions, the system in a liquid carrier is highly magnetically responsive. In liquid, a spatial redistribution of the initially homogeneously dispersed phase in the vicinity of the nanocluster is observed, an effect that is reminiscent of the so-called haloing effect previously observed experimentally on micro- and milliscales.
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Affiliation(s)
- Andrey A Kuznetsov
- Computational and Soft Matter Physics, Faculty of Physics, University of Vienna, Kolingasse 14-16, 1090 Vienna, Austria
| | - Sofia S Kantorovich
- Computational and Soft Matter Physics, Faculty of Physics, University of Vienna, Kolingasse 14-16, 1090 Vienna, Austria
- Research Platform MMM Mathematics-Magnetism-Material, University of Vienna, Oskar-Morgenstern-Platz 1, 1090 Vienna, Austria
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2
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Shrestha S, Wang B, Dutta P. Nanoparticle processing: Understanding and controlling aggregation. Adv Colloid Interface Sci 2020; 279:102162. [PMID: 32334131 DOI: 10.1016/j.cis.2020.102162] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/13/2020] [Accepted: 04/14/2020] [Indexed: 12/22/2022]
Abstract
Nanoparticles (NPs) are commonly defined as particles with size <100 nm and are currently of considerable technological and academic interest, since they are often the starting materials for nanotechnology. Novel properties develop as a bulk material is reduced to nanodimensions and is reflected in new chemistry, physics and biology. With reduction in size, a greater function of the atoms is at the surface, and promote different interaction with its environment, as compared to the bulk material. In addition, the reduction in size alters the electronic structure of the material, resulting in novel quantum effects. Size also influences mobility, primarily controlled by Brownian motion for NPs, and relevant in biological and environmental processes. However, the small size also leads to high surface energy, and NPs tend to aggregate, thereby lowering the surface energy. In all applications, the uncontrolled aggregation of NPs can have negative effects and needs to be avoided. There are however examples of controlled aggregation of NPs which give rise to novel effects. This review article is focused on the NP features that influences aggregation. Common strategies for synthesis of NPs from the gas and liquid phases are discussed with emphasis on aggregation during and after synthesis. The theory involving Van der Waals attractive force and electrical repulsive force as the controlling features of the stability of NPs is discussed, followed by examples of how repulsive and attractive forces can be manipulated experimentally to control NP aggregation. In some applications, NPs prepared by liquid methods need to be isolated for further applications. The process of solvent removal introduces new forces such as capillary forces that promote aggregation, in many cases, irreversibly. Strategies for controlling aggregation upon drying are discussed. There are also many methods for redispersing aggregated NPs, which involve mechanical forces, as well as manipulating capillary forces and surface characteristics. We conclude this review with a discussion of aggregation relevant real-world applications of NPs. This review should be relevant for scientists and technologists interested in NPs, since emphasis has been on the practical aspects of NP-based technology, and especially, strategies relevant to controlling NP aggregation.
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Affiliation(s)
- Sweta Shrestha
- ZeoVation, 1275 Kinnear Road, Columbus, OH 43212, United States of America
| | - Bo Wang
- ZeoVation, 1275 Kinnear Road, Columbus, OH 43212, United States of America
| | - Prabir Dutta
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States of America.
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3
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Sezer N, Atieh MA, Koç M. A comprehensive review on synthesis, stability, thermophysical properties, and characterization of nanofluids. POWDER TECHNOL 2019. [DOI: 10.1016/j.powtec.2018.12.016] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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4
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Effect of γ-Fe2O3 nanoparticles on rheological and volumetric properties of solutions containing polyethylene glycol. INTERNATIONAL JOURNAL OF INDUSTRIAL CHEMISTRY 2017. [DOI: 10.1007/s40090-017-0132-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Mrlík M, Ilčíková M, Cvek M, Pavlínek V, Zahoranová A, Kroneková Z, Kasak P. Carbonyl iron coated with a sulfobetaine moiety as a biocompatible system and the magnetorheological performance of its silicone oil suspensions. RSC Adv 2016. [DOI: 10.1039/c6ra03919g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In this study, surface modification of carbonyl iron (CI) particles with sulfobetaine moieties (SBE) was performed by the silanization of activated CI to form stable CI–SBE particles.
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Affiliation(s)
- Miroslav Mrlík
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - Markéta Ilčíková
- Polymer Institute
- Slovak Academy of Sciences
- Bratislava 45
- Slovakia
- Centre for Advanced Materials
| | - Martin Cvek
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - Vladimír Pavlínek
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - Anna Zahoranová
- Polymer Institute
- Slovak Academy of Sciences
- Bratislava 45
- Slovakia
| | - Zuzana Kroneková
- Polymer Institute
- Slovak Academy of Sciences
- Bratislava 45
- Slovakia
| | - Peter Kasak
- Centre for Advanced Materials
- Qatar University
- Doha
- Qatar
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6
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Iyengar SJ, Joy M, Mohamed AP, Samanta S, Ghosh CK, Ghosh S. Fabrication of magnetite nanocrystals in alcohol/water mixed solvents: catalytic and colloid property evaluation. RSC Adv 2016. [DOI: 10.1039/c6ra11225k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Size tailoring in alcohol–water mixed solvents produces small magnetite nanocrystals with appreciably high catalytic activities that form ultrastable colloids when suspended in water.
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Affiliation(s)
- Srividhya J. Iyengar
- Project Management Division
- CSIR-Central Glass & Ceramics Research Institute
- Kolkata-700032
- India
| | - Mathew Joy
- Project Management Division
- CSIR-Central Glass & Ceramics Research Institute
- Kolkata-700032
- India
| | - A. Peer Mohamed
- Functional Materials Section (MSTD)
- CSIR-National Institute for Interdisciplinary Science & Technology (NIIST)
- Trivandrum-695019
- India
| | - Swati Samanta
- Material Characterization & Instrumentation Division
- CSIR-Central Glass & Ceramic Research Institute
- Kolkata-700032
- India
| | - Chandan Kumar Ghosh
- School of Material Science & Nanotechnology
- Jadavpur University
- Kolkata-700032
- India
| | - Swapankumar Ghosh
- Project Management Division
- CSIR-Central Glass & Ceramics Research Institute
- Kolkata-700032
- India
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7
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Thermal conductivity, viscosity and surface tension of nanofluids based on FeC nanoparticles. POWDER TECHNOL 2015. [DOI: 10.1016/j.powtec.2015.06.040] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Experimental investigation on thermal conductivity of water based nickel ferrite nanofluids. ADV POWDER TECHNOL 2015. [DOI: 10.1016/j.apt.2015.08.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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The biomechanisms of metal and metal-oxide nanoparticles' interactions with cells. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:1112-34. [PMID: 25648173 PMCID: PMC4344658 DOI: 10.3390/ijerph120201112] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 12/31/2014] [Accepted: 01/14/2015] [Indexed: 12/05/2022]
Abstract
Humans are increasingly exposed to nanoparticles (NPs) in medicine and in industrial settings, where significant concentrations of NPs are common. However, NP interactions with and effects on biomolecules and organisms have only recently been addressed. Within we review the literature regarding proposed modes of action for metal and metal-oxide NPs, two of the most prevalent types manufactured. Iron-oxide NPs, for instance, are used as tracers for magnetic resonance imaging of oncological tumors and as vehicles for therapeutic drug delivery. Factors and theories that determine the physicochemical and biokinetic behaviors of NPs are discussed, along with the observed toxicological effects of NPs on cells. Key thermodynamic and kinetic models that explain the sources of energy transfer from NPs to biological targets are summarized, in addition to quantitative structural activity relationship (QSAR) modeling efforts. Future challenges for nanotoxicological research are discussed. We conclude that NP studies based on cell culture are often inconsistent and underestimate the toxicity of NPs. Thus, the effect of NPs needs to be examined in whole animal systems.
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Machovský M, Mrlík M, Plachý T, Kuřitka I, Pavlínek V, Kožáková Z, Kitano T. The enhanced magnetorheological performance of carbonyl iron suspensions using magnetic Fe3O4/ZHS hybrid composite sheets. RSC Adv 2015. [DOI: 10.1039/c4ra14054k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The facile two-step microwave-assisted synthesis of Fe3O4/ZHS hybrid composite sheets with 2D morphology considerably improves the MR performance and suspension redispersibility.
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Affiliation(s)
- Michal Machovský
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlin
- 760 01 Zlin
- Czech Republic
| | - Miroslav Mrlík
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlin
- 760 01 Zlin
- Czech Republic
| | - Tomáš Plachý
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlin
- 760 01 Zlin
- Czech Republic
| | - Ivo Kuřitka
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlin
- 760 01 Zlin
- Czech Republic
| | - Vladimír Pavlínek
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlin
- 760 01 Zlin
- Czech Republic
| | - Zuzana Kožáková
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlin
- 760 01 Zlin
- Czech Republic
| | - Takeshi Kitano
- Centre of Polymer Systems
- University Institute
- Tomas Bata University in Zlin
- 760 01 Zlin
- Czech Republic
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11
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Shen C, Wu L, Zhang S, Ye H, Li B, Huang Y. Heteroaggregation of microparticles with nanoparticles changes the chemical reversibility of the microparticles' attachment to planar surfaces. J Colloid Interface Sci 2014; 421:103-13. [PMID: 24594038 PMCID: PMC7094237 DOI: 10.1016/j.jcis.2014.01.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 01/24/2014] [Accepted: 01/24/2014] [Indexed: 11/18/2022]
Abstract
We theoretically examine detachment of homo- and heteroaggregates from primary minima. Attached homoaggregates in primary minima are irreversible to reduction in ionic strength. The attachment of microparticles coated by nanoparticles is chemically reversible. We explain observed disaggregation of particles from primary minima in the literature. We explain why viruses exhibit most conservative transport behavior in the environment.
This study theoretically investigated detachment of homoaggregates and heteroaggregates attached on the planar surfaces at primary minima during transients in solution chemistry. The homoaggregates were represented as small colloidal clusters with well-defined structures or as clusters generated by randomly packing spheres using Monte Carlo method. The heteroaggregates were modeled as microparticles coated with nanoparticles. Surface element integration technique was adopted to calculate Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energies for the homoaggregates and heteroaggregates at different ionic strengths. Results show that attached homoaggregates on the planar surface at primary minima are irreversible to reduction in solution ionic strength whether the primary spheres of the homoaggregates are nano- or micro-sized. Heteroaggregation of nanoparticles with a microparticle can cause DLVO interaction energy to decrease monotonically with separation distance at low ionic strengths (e.g., ⩽0.01 M), indicating that the heteroaggregates experience repulsive forces at all separation distances. Therefore, attachment of the heteroaggregates at primary minima can be detached upon reduction in ionic strength. Additionally, we showed that the adhesive forces and torques that the aforementioned heteroaggregates experience can be significantly smaller than those experienced by the microspheres without attaching nanoparticles, thus, the heteroaggregates are readily detached via hydrodynamic drag. Results of study provide plausible explanation for the observations in the literature that attached/aggregated particles can be detached/redispersed from primary minima upon reduction in ionic strength, which challenges the common belief that attachment/aggregation of particles in primary minima is chemically irreversible.
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Affiliation(s)
- Chongyang Shen
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China.
| | - Lei Wu
- Department of Agricultural and Biological Engineering, University of Florida, FL 32611, United States
| | - Shiwen Zhang
- School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China
| | - Huichun Ye
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Baoguo Li
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Yuanfang Huang
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China.
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12
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Machovsky M, Mrlik M, Kuritka I, Pavlinek V, Babayan V. Novel synthesis of core–shell urchin-like ZnO coated carbonyl iron microparticles and their magnetorheological activity. RSC Adv 2014. [DOI: 10.1039/c3ra44982c] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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13
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Stability, rheological, magnetorheological and volumetric characterizations of polymer based magnetic nanofluids. Colloid Polym Sci 2013. [DOI: 10.1007/s00396-013-2936-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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14
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Abstract
Diester based magnetic fluid is a novel intelligent material which use diester as carrier liquid and magnetic iron ore as magnetic nano-particles combined together with proper surfactant. Its specially unique characteristic contributes to wide applications in engineering research field such as magnetic fluid based seals, magnetic fluid based dampers and so on. This paper provides a method of diester-based magnetic fluid synthesis and analysis for the properties of prepared diester magnetic fluid as well as effective influencing parameters. The results show that for getting proper size and magnetization of magnetic particles, the proper reacted temperature is around 60~80°C, appropriate molar ratio of reacted solution is 1.75 and concentration of forerunner is about 0.6 mol/L. It is also found that the viscosity of diester-based magnetic fluid is decreased with environment temperature while the viscosity as well as saturation magnetization increases with the increment of density.
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15
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Magnet C, Kuzhir P, Bossis G, Meunier A, Suloeva L, Zubarev A. Haloing in bimodal magnetic colloids: the role of field-induced phase separation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:011404. [PMID: 23005414 DOI: 10.1103/physreve.86.011404] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 06/20/2012] [Indexed: 06/01/2023]
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. López-López, 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 (φ(0)) and the magnetic-to-thermal energy ratio (α)--and the three accumulation regimes are mapped onto a α-φ(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.
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Affiliation(s)
- C Magnet
- Laboratory of Condensed Matter Physics, University of Nice Sophia Antipolis, CNRS UMR 7663, Parc Valrose, 06108 Nice Cedex 2, France
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16
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Iglesias GR, López-López MT, Durán JDG, González-Caballero F, Delgado AV. Dynamic characterization of extremely bidisperse magnetorheological fluids. J Colloid Interface Sci 2012; 377:153-9. [PMID: 22520211 DOI: 10.1016/j.jcis.2012.03.077] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/16/2012] [Accepted: 03/24/2012] [Indexed: 11/28/2022]
Abstract
In this work, we investigate the stability and redispersibility of magnetorheological fluids (MRFs). These are disperse systems where the solid is constituted by ferro- or ferri-magnetic microparticles. Upon the application of external magnetic field, they experience rapid and reversible increases in yield stress and viscosity. The problem considered here is first of all the determination of their stability against sedimentation, an essential issue in their practical application. Although this problem is typically faced through the addition of thixotropic agents to the liquid medium, in this work, we propose the investigation of the effect of magnetic nanoparticles addition, so that the dispersion medium is in reality a ferrofluid. It is found that a volume fraction of nanoparticles not higher than 3% is enough to provide a long-lasting stabilization to MRFs containing above 30% iron microparticles. In the, in fact unavoidable, event of settling, the important point is the ease of redispersion of the sediment. This is indirectly evaluated in the present investigation by measuring the penetration force in the suspension, using a standard hardness needle. Again, it is found that the nanoparticles addition produces soft sediments by avoiding short-range attractions between the large iron particles. Finally, the performance of the designed MRFs is evaluated by obtaining their steady-state rheograms for different volume fractions of magnetite and different magnetic field strengths. The yield stress is found to be strongly field-dependent, and it can achieve the high values expected in standard magnetorheological fluids but with improved stability and redispersibility.
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Affiliation(s)
- G R Iglesias
- Department of Applied Physics, School of Science University of Granada, 18071 Granada, Spain.
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17
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Liu X, Chen G, Su C. Effects of material properties on sedimentation and aggregation of titanium dioxide nanoparticles of anatase and rutile in the aqueous phase. J Colloid Interface Sci 2011; 363:84-91. [DOI: 10.1016/j.jcis.2011.06.085] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 06/22/2011] [Accepted: 06/30/2011] [Indexed: 11/28/2022]
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18
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Iglesias GR, López-López MT, Delgado AV, Durán JDG. Description and performance of a fully automatic device for the study of the sedimentation of magnetic suspensions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:073906. [PMID: 21806198 DOI: 10.1063/1.3609228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this paper we describe an experimental setup for the automatic determination of the sedimentation behavior of magnetic suspensions (i.e., disperse systems consisting on ferro- or ferri-magnetic particles in a suitable fluid) of arbitrary volume fraction of solids. The device is based on the evaluation of the inductance of a thin coil surrounding the test tube containing the sample. The inductance L is evaluated from the measurement of the resonant frequency of a parallel LC circuit constructed with the coil and a capacitor of known capacitance. The coil can be moved vertically along the tube at specified steps and time intervals, and from the knowledge of L as a function of the vertical position and time, one can get an image of the particle concentration profiles at given instants of time. The performance of the device is tested against suspensions of spherical iron particles in the micrometer size range dispersed in silicone oil, with various initial concentrations of solids. The sedimentation profiles are then compared with the predictions of existing models for the settling of disperse systems of non-interacting particles.
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Affiliation(s)
- G R Iglesias
- Institute of Physical Chemistry, University of Graz, 8010 Graz, Austria
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19
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Ramos-Tejada MM, Arroyo FJ, Delgado AV. Negative electrorheological behavior in suspensions of inorganic particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:16833-16840. [PMID: 20939556 DOI: 10.1021/la1029036] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An investigation is described on the electric-field-induced structures in colloidal dispersions. Both rheological determinations and direct microscopic observations are used with that aim. The starting point of this study is the so-called electrorheological (ER) effect, consisting of the mechanical reinforcing of a fluid or suspension due to formation of chains of molecules or particles after being polarized by the action of the field. One macroscopic manifestation of this phenomenon is the transformation of the fluid from a typically Newtonian behavior to a viscoelastic material, with finite yield stress and high elastic modulus. The systems investigated were suspensions of elongated goethite (β-FeOOH) particles in silicone oils with varying amounts of silica nanoparticles. The results showed the rather unusual behavior known as "negative ER effect", which can be best described by saying that the application of an electric field reduces the yield stress and the elastic modulus, that is, produces destruction of structures rather than their build up. The negative behavior is also found for suspensions of other inorganic powders, including hematite and quartz. On the contrary, the usual positive ER response is found for suspensions of cellulose and montmorillonite clay. The same happens if goethite suspensions are prepared in high volume fractions, high-viscosity fluids, or both. All of the results found are compatible with the so-called interfacial model of electrorheology: the reduction of the yield stress of goethite suspensions when the applied field is high enough is the consequence of particle migration toward the electrodes because of charge injection and subsequent electrophoresis. The migration leaves the gap between the electrodes devoid of particles and explains the decrease in yield stress. The addition of silica nanoparticles contributes to reduce the strength of this effect by hindering the charging and making it necessary to increase the field strength to observe the negative effect. The model appears to also be applicable to cellulose, although the positive response found for such particles is explained by their large size: larger diameters bring about larger attraction forces between particles, leading to a tendency to produce strong aggregates. This is likely to occur in suspensions of colloids which, because of their relatively high electrical conductivity, tend to acquire charge even in such nonpolar liquids as silicone oils.
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Affiliation(s)
- M M Ramos-Tejada
- Departamento de Física, Escuela Politécnica Superior de Linares, Universidad de Jaén, Linares 23700, Spain
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20
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Hotze EM, Phenrat T, Lowry GV. Nanoparticle aggregation: challenges to understanding transport and reactivity in the environment. JOURNAL OF ENVIRONMENTAL QUALITY 2010; 39:1909-24. [PMID: 21284288 DOI: 10.2134/jeq2009.0462] [Citation(s) in RCA: 582] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Unique forms of manufactured nanomaterials, nanoparticles, and their suspensions are rapidly being created by manipulating properties such as shape, size, structure, and chemical composition and through incorporation of surface coatings. Although these properties make nanomaterial development interesting for new applications, they also challenge the ability of colloid science to understand nanoparticle aggregation in the environment and the subsequent effects on nanomaterial transport and reactivity. This review briefly covers aggregation theory focusing on Derjaguin-Landau-Verwey-Overbeak (DLVO)-based models most commonly used to describe the thermodynamic interactions between two particles in a suspension. A discussion of the challenges to DLVO posed by the properties of nanomaterials follows, along with examples from the literature. Examples from the literature highlighting the importance ofaggregation effects on transport and reactivity and risk of nanoparticles in the environment are discussed.
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Affiliation(s)
- Ernest M Hotze
- Center for Environmental Implications of NanoTechnology (CEINT) and Deps. of Civil & Environmental Engineering, Carnegie Mellon Univ., Pittsburgh, PA 15213-3890, USA
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21
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Viota JL, Durán JDG, Delgado AV. Study of the magnetorheology of aqueous suspensions of extremely bimodal magnetite particles. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2009; 29:87-94. [PMID: 19430949 DOI: 10.1140/epje/i2009-10453-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 02/05/2009] [Accepted: 03/13/2009] [Indexed: 05/27/2023]
Abstract
In this paper we describe the magnetorheological behavior of aqueous suspensions consisting of magnetite particles of two size populations, in the micrometer and nanometer scale, respectively. Previous works on the magnetorheology of oil-based fluids demonstrated that the addition of nanoparticles has a very significant effect on the intensity of the magnetorheological effect. The present contribution confirms such results in the case of aqueous fluids, based on the dependence of the yield stress and the viscosity of the bimodal suspensions on both the composition of the mixtures and the magnetic field strength. It is demonstrated that for a given concentration of micrometer particles, increasing the amount of nanometer magnetite provokes a clear enhancement in the yield stress for all the magnetic fields applied. This is proposed to be due to the formation of heterogeneous aggregates that improve the stability of the suspensions and ease the building of well-arranged field-induced structures. The behavior of both the yield stress and the post-yield viscosity agrees better with the predictions of standard chain models when the relative proportion of both types of particles confers optimum stability to the bimodal dispersions.
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Affiliation(s)
- J L Viota
- Department of Physics, University of Jaén, 23071, Jaén, Spain
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Viota J, Delgado A, Arias J, Durán J. Study of the magnetorheological response of aqueous magnetite suspensions stabilized by acrylic acid polymers. J Colloid Interface Sci 2008; 324:199-204. [DOI: 10.1016/j.jcis.2008.05.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Revised: 05/14/2008] [Accepted: 05/16/2008] [Indexed: 10/22/2022]
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López-López MT, Gómez-Ramírez A, Durán JDG, González-Caballero F. Preparation and characterization of iron-based magnetorheological fluids stabilized by addition of organoclay particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7076-7084. [PMID: 18540642 DOI: 10.1021/la703519p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Suspensions of micrometer-sized iron particles (10 vol %) dispersed in kerosene and stabilized by addition of organoclay particles were prepared. The magnetization curves of these suspensions were measured, and their sedimentation and redispersion behaviors were analyzed as a function of clay concentration by means of optical and rheological methods. Furthermore, their magnetorheological properties were investigated using a controlled rate magnetorheometer and the effect of clay concentration on these properties was also analyzed. These experiments showed that the addition of clay slows down iron particle settling and eases the redispersion of the iron-based suspensions without masking their magnetorheological properties. Two mechanisms were found to be involved in this behavior: (i) the formation of a clay gel network and (ii) the presence of heterogeneous iron-clay adhesion.
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Affiliation(s)
- Modesto T López-López
- Department of Applied Physics, Faculty of Sciences, University of Granada, Avda Fuentenueva s/n, 18071 Granada, Spain.
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