Aggregation dynamics and magnetic properties of magnetic micrometer-sized particles dispersed in a fluid under the action of rotating magnetic fields

Llera, María; Codnia, Jorge; Jorge, G. A.

doi:10.1016/j.jmmm.2015.02.025

Cited by 16 publications

(4 citation statements)

References 23 publications

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“…It should be noted the tendency of magnetic fluids to lose colloidal stability, an insufficiently wide temperature range of operation, destruction upon contact with many liquid media, and much more. For example, the use of magnetic fluids in friction units and seals is hindered by their tendency to structure formation in strong magnetic fields [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Study of the laws of internal friction in magnetic fluids with a strongly developed thixotropic nanostructure

Bolotov,

Novikova,

Novikov

2023

E3S Web of Conf.

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Due to their unique physical properties, magnetic fluids are promising for use in bearings, seals, sliding guides, and other devices of modern technology. Some restrictions on their use are imposed by the tendency of magnetic fluids to lose colloidal stability and structure formation in strong magnetic fields. Increasing the stability of a colloid by reducing the size of the dispersed particles of the magnetic fluid is limited by the Heisenberg uncertainty relation, on the condition of maintaining their ferromagnetic state. The search for ways to reduce internal friction in technical devices with magnetic fluids having a highly developed thixotropic nanostructure is important from a practical point of view. Using a device, simulating the operation of a magnetohydrostatic bearing, the rheological characteristics of a fluid nanostructured by a magnetic field, which is a colloidal system with a dispersed phase of magnetite particles (10 vol.%) and a dispersion medium of silicon organic fluid PESV-2, were studied. The dynamic viscosity of the magnetic fluid was about 0.05 Pa.s at 20°C. It has been established that the process of structuring a magnetic fluid in an external field can last hundreds of hours and depends mainly on the viscosity of the dispersion medium and the concentration of magnetite. It has been revealed that the motion of a cylinder with a terminal velocity begins only at shear stresses exceeding the limiting static stress and proceeds at a constant velocity. The breakdown of the structure begins after the shear stress exceeds the critical value. The critical stress is introduced to compare the strength of the structure of different fluids. The value of the critical stress was determined with an accuracy of up to 50 Pa by analyzing the curves of the change in the sliding speed with time. It has been established that the temperature dependence of the critical shear stress is very sharp and close to exponential.

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Section: Introductionmentioning

confidence: 99%

Study of the laws of internal friction in magnetic fluids with a strongly developed thixotropic nanostructure

Bolotov,

Novikova,

Novikov

2023

E3S Web of Conf.

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“…This technique is used for many applications such as bacteria processing, cell separation, chromatography, protein isolation, waste capture, etc [28,31,[39][40][41][42][43][44][45][46][47]. Superparamagnetic colloids are also well-known for the more complex structures they form under more complex fields, potentially leading to microbots [33,34,[48][49][50][51][52][53][54][55][56]. Those controllable assemblies open ways to new kinds of applications thanks to their unique optical properties and versatility to execute various tasks [50,51,54,57].…”

Section: Introductionmentioning

confidence: 99%

Combined effects of Marangoni, sedimentation and coffee-ring flows on evaporative deposits of superparamagnetic colloids

Darras

Vandewalle²,

Lumay³

2019

Colloid and Interface Science Communications

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Evaporation of sessile colloidal droplets is a way to organize suspended particles. It is already known that the composition of the surrounding fluid modifies the dried deposit. For superparamagnetic particles, recent studies showed that external magnetic fields can act as remote controls for those deposits. In this paper, we study the configuration space given by the interplay of such fields and a modification of the fluid composition by considering various concentrations of phosphate buffered saline (PBS). We show that the magnetic field modifies the morphological properties of the deposit, while the composition (i.e. PBS concentration) modifies the density profile of the deposit. We then present an explanation of these influences considering the competition between (i) sedimentation, (ii) coffee-ring and (iii) Marangoni flows. From these considerations, we propose a master curve which should be able to model the deposit densities of any system where the above mechanisms compete with each other.

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“…However, to achieve high magnetic performance, rubbers have to be filled with a large content of Fe 3 O 4 , consequently accompanying with an unwilling decreased mechanical property due to the weak interactions between Fe 3 O 4 nanoparticles and rubber matrix, as well as the unsatisfactory dispersion of Fe 3 O 4 nanoparticles. , Organic modification is a commonly applied method to improve the interfacial compatibility and the dispersion of fillers in rubbers. Unfortunately, in most cases, the organic treated Fe 3 O 4 nanoparticles have a strong tendency to aggregate together at a dried status, − which hinders their dispersion in rubber compounding. Although the aggregation of organic treated Fe 3 O 4 nanoparticles can be solved in a solution state, the available rubber latexes are quite limited and the subsequent drying, compounding and vulcanization of rubbers add cost.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of High Performance Magnetic Rubber from NBR and Fe₃O₄via in Situ Compatibilization with Zinc Dimethacrylate

Chen

Huang

Gong

et al. 2016

Ind. Eng. Chem. Res.

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Fe 3 O 4 -based magnetic rubbers are desirable because they take advantage of high elasticity, large elongations, and high magnetic saturation intensity of each component. However, direct compounding of rubbers and Fe 3 O 4 usually resulted in low mechanical properties which made the magnetic rubbers unable to satisfy practical applications. In this paper, we prepared nitrile butadiene rubber (NBR)/Fe 3 O 4 -based magnetic rubbers with good mechanical properties by means of in situ compatibilization using zinc dimethacrylate (ZDMA). Our strategy was based on the polymerization of ZDMA during a peroxide-induced vulcanization, in which the polymerized ZDMA (PZDMA) brought massive Zn 2+ ion pairs into NBR. Zn 2+ ion pairs not only increased the polarity of NBR but also strongly interacted with Fe 3 O 4 nanoparticles. Because of the graf t-PZDMA, the Zn 2+ ion pairs finally strengthened interactions between Fe 3 O 4 nanoparticles and NBR molecules. We hope this report laid an applied foundation for design of high performance magnetic rubbers to satisfy the various potential applications.

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Aggregation dynamics and magnetic properties of magnetic micrometer-sized particles dispersed in a fluid under the action of rotating magnetic fields

Cited by 16 publications

References 23 publications

Study of the laws of internal friction in magnetic fluids with a strongly developed thixotropic nanostructure

Study of the laws of internal friction in magnetic fluids with a strongly developed thixotropic nanostructure

Combined effects of Marangoni, sedimentation and coffee-ring flows on evaporative deposits of superparamagnetic colloids

Fabrication of High Performance Magnetic Rubber from NBR and Fe₃O₄via in Situ Compatibilization with Zinc Dimethacrylate

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Aggregation dynamics and magnetic properties of magnetic micrometer-sized particles dispersed in a fluid under the action of rotating magnetic fields

Cited by 16 publications

References 23 publications

Study of the laws of internal friction in magnetic fluids with a strongly developed thixotropic nanostructure

Study of the laws of internal friction in magnetic fluids with a strongly developed thixotropic nanostructure

Combined effects of Marangoni, sedimentation and coffee-ring flows on evaporative deposits of superparamagnetic colloids

Fabrication of High Performance Magnetic Rubber from NBR and Fe3O4via in Situ Compatibilization with Zinc Dimethacrylate

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Product

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Fabrication of High Performance Magnetic Rubber from NBR and Fe₃O₄via in Situ Compatibilization with Zinc Dimethacrylate