Magnetic Fluid Nanoparticles Research Articles

Force analysis and distribution evolution of Fe3O4 nanoparticles in magnetic fluids

The effective utilization of magnetic nanoparticles in ferromagnetic fluids relies on their distribution and properties, which can be influenced by their arrangement at both micro and macro scales. In this paper, we present a dynamic model to analyze the motion and forces of nanoparticles in magnetic fluids, aiming to describe their distribution evolution under magnetic and flow fields. Finite element simulations using COMSOL software are employed, and a dimensionless ordering coefficient is proposed to quantitatively evaluate the status of nanoparticle distribution. The results indicate that reducing fluid viscosity, increasing magnetic field strength, and increasing magnetic particle radius can facilitate the attainment of an optimal ordered state for nanoparticles in magnetic fluids. However, prolonged exposure to a magnetic field can lead to particle agglomeration, hindering the effective manipulation of nanoparticles. To mitigate rapid agglomeration, we employ an intermittent magnetic field exposure strategy during the curing process of a magnetic slurry consisting of PVDF, DMF, and Fe3O4 nanoparticles. The tests reveal that with increasing magnetic field exposure time, the increase rate of the ordering coefficient initially progresses slowly, then gradually accelerates, and eventually reaches equilibrium. This approach successfully addresses the rapid agglomeration of magnetic particles observed in the simulation results. Consequently, precise control over the nanoparticle radius, magnetic field strength, and carrier fluid viscosity allows for meticulous regulation of the ordered distribution state of magnetic particles. This breakthrough has significant potential in expanding the application and research opportunities of magnetic materials.

Sealing performance in a spiral groove mechanical seal lubricated by magnetic fluid

PurposeMagnetic fluid has excellent function used as lubricants in bearings and mechanical seals, and the purpose of this study is to investigate the sealing performance in a spiral groove mechanical seal lubricated by magnetic fluid.Design/methodology/approachThe sealing characteristic parameters of the lubricating film between the end faces of two sealing rings were calculated based on the Muijderman narrow groove theory for a spiral groove mechanical seal lubricated by magnetic fluid. The film thickness was determined according to the balanced forces on the rotating ring, and the effects of operating conditions, intensity of the magnetic field and diameter of nanoparticles on the sealing characteristics were investigated.FindingsIt has been found that the intensity of magnetic field has a great effect on the viscosity of magnetic fluid, film thickness and friction torque while has a little effect on the mass flux of magnetic fluid. The film thickness, mass flux of magnetic fluid and friction torque increase with the increasing volume fraction, rotating speed and diameter of magnetic nanoparticles in magnetic fluid. The mass flux of magnetic fluid decrease with the increasing closing force, and the friction torque decreases with the increase of media pressure.Originality/valueThe change of intensity of magnetic field can affect the viscosity of magnetic fluid and then changes the sealing performance in a mechanical seal lubricated by magnetic fluid. To reduce the mass flux of magnetic fluid and friction torque, the volume fraction, diameter of solid magnetic particles and film thickness should be 5%–7%, 8–10 nm and 2–9.3 µm, respectively.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2023-0032/

Investigation of structures formed by magnetic fluid nanoparticles in polymer matrices by static light scattering

Investigation of structures formed by magnetic fluid nanoparticles in polymer matrices by static light scattering

Fiber Vector Magnetometer Based on Polarization-Maintaining Fiber Long-Period Grating With Ferrofluid Nanoparticles

An opticalfiber vector magnetometer based on a thin-cladding polarization-maintaining fiber (TPMF) long-period fiber grating (LPFG) and magnetic fluid (MF) is proposed and experimentally demonstrated. The non-circular symmetric fiber structure and asymmetric evanescence field distribution of the LPFG induce a vector surrounding refractive index (SRI) response. Based on the magneto-optical properties of the MF nanoparticles and the directional SRI characteristics of the TPMF-LPFG, the resonance dip wavelength shift of the grating is dependent on the angle between the principal axis of TPMF and the external magnetic field direction when being applied to an external magnetic field. The achieved maximum sensitivity of the wavelength shift was −618 pm/mT when the magnetic intensity changes in the range of 0–10.5 mT. The achieved maximum orientation sensitivity of the sensor was 72 pm/degree, but the magnetic orientation can be detected only within the range of 0–90 degree. The minimum magnetic field intensity that can be detected is about 32.3 μT due to the 0.02 nm wavelength resolution of the optical spectrum analyzer. Our study proves that the high birefringence fiber based LPFG combined with MF can be developed as a high-performance vector magnetometer and such type of sensor is anticipated to find potential applications in magnetic or electric field systems.

Modeling the effect of surfactant (linoleic acid/oleic acid/stearic acid) on the stability of kerosene-based magnetic fluid with Fe3O4

The poor stability of magnetic fluid is a key problem which limits its application. To understand the impact of surfactants on stability, we prepare kerosene-based magnetic fluid with Fe3O4 magnetic nanoparticles (MNPs) using different surfactants i.e. linoleic acid, oleic acid and stearic acid. The distribution of nanoparticles in magnetic fluid is obtained by transmission electron microscope (TEM) and granularity analyzer. We find that MNPs coated with stearic acid agglomerate and the size is the largest. In contrast, the MNPs coated with linoleic acid or oleic acid are well dispersed with smaller size, which reveals that the type of surfactant will affect the stability of the magnetic fluid. To understand this, the adhesion energy of surfactant on particles and the solvation energy of surfactant in carrier fluid are calculated by ab initio and molecular dynamics. Based on the calculation results, we propose a formula for estimating the stability of magnetic fluid by combining the repulsive energy between Fe3O4 nanoparticles covered by surfactant and the calculated solvation energy of surfactants and carrier fluid, which can well interpret our experimental results. Our study reveals the mechanism of magnetic fluid stability and provides theoretical guidance for the preparation of stable magnetic fluid.

INFLUENCE OF MAGNETIC NANOPARTICLES ON ACOUSTIC ATTENUATION IN LIQUIDS

Magnetic fluids with nanoparticles dispersed in water or oils offer attractive applications in biomedicine and industry. Biocompatible magnetic fluids are used for diagnostics and therapy in medical applications, in pharmacy, and biosensors. Application of ferrofluids is expanding into energy conservation, faster and efficient cooling, and hence better performance in a wide variety of practical applications (in heat exchangers, mainly in micro-cooling systems). For the study of the influence of an external magnetic field on the aggregation processes of magnetic nanoparticles in magnetic fluids, acoustic spectroscopy was used. The jump changes of the magnetic flux density at various temperatures influenced the acoustic attenuation. The measured changes were results of nanoparticle aggregations into new structures.

Development and study of protective properties of the composite materials for shielding the electromagnetic fields of a wide frequency range

Composites were shown to be the most promising materials for protection against electromagnetic fields. A technology of magnetic treatment of textile material with magnetic fluid and technology of ultrasonic treatment of a mixture of latex and iron ore concentrate has been developed. This has increased saturation of fibers of the textile material with magnetic fluid nanoparticles, dispersity of the iron ore concentrate, and isotropy of the liquid metal-polymer material. As a result of the use of this technology, the consumption of magnetic fluid for the treatment of the textile material decreased from 45‒50 g/m2 to 35 g/m2 with an improvement of shielding properties. It has been experimentally established that one layer of metal-textile material reduces the magnetic field of industrial frequency by 6 times and the electric field of industrial frequency by 1.5 times. Corresponding figures for the metal-polymer material were 3 and 2. It was found that an electromagnetic field with a frequency of 2.45 GHz is reduced 3.6 times by the single-layer metal-textile material and 5.7 times by the metal-polymer material. It was shown that the metal-textile material with such properties is suitable for the manufacture of personal protective means for personnel operating electrical and radio transmission equipment. Metal-polymeric material is suitable for the manufacture of collective protective means. A calculated evaluation of the effectiveness of protective materials was proposed. It is based on determining the shielding factors of structures of standard shapes. This enables the determination of electrophysical and magnetic properties of the material and their use in the development of protective materials with required shielding factors. The necessity of optimization of shielding factors under conditions of simultaneous influence of electromagnetic fields of heterogeneous sources was substantiated

In Ukrainian

The purpose of the review is to analyze and summarize the results of the works performed at Chuiko Institute of Surface Chemistry of NAS of Ukraine, dedicated to the synthesis and study of the properties of new magnetic fluids (MF) containing NC of superparamagnetic core – multilevel shell type and characterized by the functions of medico-biologic nanorobots. The research themes are focused on the creation of the latest medical theranostic remedies for targeted delivery and local complex treatment, primarily for needs of oncology. The methodology of the work includes formulation of the problem of synthesis of NC of superparamagnetic core-multilevel shell type with the functions of biomedical nanorobots, relative MF, comprehensive studies of magnetic, structural and rheological characteristics, sedimentation stability, antitumor activity in vitro, in vivo. It has been shown that calculations of the magnetization curve of MF based on single-domain superparamagnetic Fe 3 O 4 , within the framework of Langevin’s theory of paramagnetism, are satisfactorily coordinated with the experimental results, assuming that the saturation magnetization of magnetite particles depends on their size. On the basis of the obtained data, the idea has been formulated of using an ensemble of magnetic fluid nanoparticles as a superparamagnetic probe to diagnose its parameters and to substantiate the development of the magnetic granulometry method and the possibility of its application to measure the size parameters of a complex shell structure of magnetically sensitive nanocomposites of superparamagnetic core – multilevel shell type. The obtained data develop the physicochemical basis for the development of new types of vector systems of anticancer drugs based on MF and have been used to improve the method of magnetic granulometry in order to optimize, standardize and control their parameters in the production process. In particular, the synthesized MF and the approaches to their magnetic diagnostics given in this work have been used in the creation of a new native oncological remedy “Feroplat” that has no analogues in the world, is a conjugate of nanoparticles of MF with cisplatin, is a standardized remedy for enhancement of the effectiveness of chemotherapy and overcoming of drug resistance of malignant neoplasms, designed to deliver cytostatic agent directly to the tumor tissue, ensuring maximal its entrance into cells and favoring an increase in the therapeutic effect. In order to be introduced into the production and clinical practice, feroplat is on a stage of completion of preclinical testing. The data are given on the cytotoxic properties and biological safety of MF containing cisplatin. It has been shown that on the general and biochemical parameters of the blood, the use of MF does not make a more toxic influence on the body, compared with the antitumor drug cisplatin in equivalent doses. The technological scheme is presented for manufacturing of a new magnetocarried polyfunctional antitumor vector system based on MF containing drugs in the structure of core-shell type nanocomposites. The results of the work are used also in the development of new magnetocarried adsorption materials for technical, technological, ecological and biomedical purposes, in the educational process of native universities in training of bachelors and masters of the corresponding specialties.

Tunable Ferrofluid Magnetic Fiber Sensor based on Nonadibatic Tapered Hi-Bi Fiber in Fiber Loop Mirror

An external magnetic field (EMF) fiber sensor by combining nanomagnetic fluid and Hi-Bi nonadiabatic tapered optical fiber in fiber loop mirror (THB-FLM) is demonstrated experimentally and theoretically. The polarization controllers (PCs) in FLM are adjusted to excite different cladding modes in the sensor. By variation of the PCs' settings, the sensitivity of the sensor to EMF in the range from 0 to 21 mT could be tuned from 255 to 402 pm/mT. As compared to the reported magnetic fluid (MF) based sensors, the achieved sensitivity of the proposed sensor, with only 0.1% of the volume concentration of MF nanoparticles, enhanced by 5.6 orders of magnitude relative to in-line nonadiabatic tapered optical fiber sensor. The detection limit of the THB-FLM to EMF in the range of 0 to 21 mT and 22 to 50 mT was 5 and 18.9 μT, respectively. Experimental results show that the sensitivity to the EMF increased with the order of the cladding mode. In addition to the EMF sensing capability, the proposed structure can simultaneously provide temperature information.

Oscillations of Magnetic Fluid Column in Strong Magnetic Field

The paper considers the results of measuring the elastic parameters (ponderomotive elasticity coefficient, oscillation frequency, attenuation coefficient) of the oscillatory system with an inertial element that is a magnetic fluid column retained in a tube due to magnetic levitation in a strong magnetic field. Elasticity is provided by the ponderomotive force which affects the upper and lower thin layers of the fluid column. Measurement results of vibration parameters of the oscillatory system can be useful for the investigations of magnetophoresis and aggregation of nanoparticles in magnetic fluids.

A Notched Long-Period Fiber Grating Magnetic Field Sensor Based on Nanoparticle Magnetic Fluid

In this paper, we propose using an inductively coupled plasma (ICP) etching technique to fabricate a notched long-period fiber grating (NLPFG) for magnetic sensing application. An optical fiber magnetic field sensor based on NLPFG filled with nanoparticle magnetic fluid is proposed and demonstrated. The magnetic fluid nanoparticles were attached on the grating structure section and used as a magneto-optical sensing layer to measure magnetic flux density. The external applied magnetic flux density ranged from 0 to 27.74 mT. As the magnetic flux density was increased, the spectra of the NLPFG were changed. The resonant wavelength of the attenuation band did not shift obviously, but the transmission loss of the resonant dip was increased by 3.48 dB from −19.41 dB to −15.93 dB. The experimental results indicated that the sensitivity of the sensor is approximately 0.125 dB/mT.

Numerical Analysis of Electromagnetic Force on Magnetic Nanoparticles in Fluid

In this paper, the nanoparticles are ferromagnetic and have charge density on the surface, and the magnetic force is coupled with the Lorentz force. To investigate the distribution of magnetic force exerted on a unit cell with different volume fraction, the nodal force method and homogenization method are applied. Lorentz force on the electric double layers of different size particles are analyzed using both 2-D and 3-D models. The calculated results show that 2-D analysis is sufficient for the analyzed nanoparticles. The proposed electromagnetic forces analysis method can be coupled to fluid and temperature analysis of nanofluid.

Определение дисперсии магнитного момента наночастиц в магнитной жидкости

Определение дисперсии магнитного момента наночастиц в магнитной жидкости

Consideration of diffuse scattering in the analysis of specular neutron reflection at the magnetic fluid-silicon interface

Neutron reflectometry data on the interface between a magnetic fluid (magnetite/sodium oleate/D2O) and silicon are considered with allowance for a background of diffuse scattering from magnetic-fluid nanoparticles adsorbed on the silicon surface. Two ways to subtract the background in selecting the specular reflection curve are analyzed. Based on a comparison of neutron reflectometry and small-angle neutron scattering data, it is concluded that individual nanoparticles rather than their aggregates (which are also present in the liquid phase) are preferably adsorbed on the silicon surface. In addition, free sodium-oleate molecules are adsorbed from the magnetic-fluid bulk.

Simulation on Microstructure and Optical Property of Magnetic Fluid Photonic Crystal

Magnetic fluid is a new functional material for optical sensors. The microstructure will be changed with various applied magnetic fields. In this paper, the molecular dynamics method based on rod-like particle was first used to simulate the microscopic movements of magnetic nanoparticles in magnetic fluid with the volume fraction of 1%. Simulation results showed that magnetic nanoparticles could aggregate to form a new type of magnetic fluid photonic crystal when the applied magnetic field intensity exceeded 180 Oe. Then, the tunability of the magnetic fluid photonic crystal was studied. It was found that the average diameter of magnetic columns would decrease when the applied magnetic field intensity was increased from 180 to 320 Oe. Furthermore, based on the simulation results, optical property of the magnetic fluid photonic crystal was studied. When the direction of the incident light was parallel to the direction of the applied magnetic field, the transmissivity would increase from 0.5944 to 0.6475, whereas when the direction of the incident light was perpendicular to the direction of the applied magnetic field, the two photonic bandgaps of transverse electric mode and TM mode all moved to higher frequency, and the two bandwidths decreased about 17% and 87%, respectively. Through the above research studies, it was proved that the magnetic fluid photonic crystal processed the magnetic tunability and would be used as a novel magnetic field sensor in the future.

Magnetic Field Sensor Based on Nonadiabatic Tapered Optical Fiber With Magnetic Fluid

A novel magnetic field sensor using a nonadiabatic tapered optical fiber (NATOF) interacting with magnetic fluid (MF) nanoparticles is proposed and experimentally demonstrated. The NATOF sensitivity when is subjected to refractive index (RI) measurement in the small range from 1.3380 to 1.3510 was 1260.17 nm/RIU as a refractometer sensor. The NATOF is surrounded by a MF whose RI changes with external magnetic field, which MF is as a cladding of tapered fiber. The output interference spectrum is shifted by the change of the applied magnetic field intensity in the range up to 44 mT with a sensitivity of -7.17 × 10 -2 nm/mT, used only 0.1% of the volume concentration of MF nanoparticles. This direct manipulation of light with magnetic fields provides an approach to develop future sensors relying on electromagnetic interactions.

Preparation and Complex Characterization of Magnetic Nanoparticles in Magnetic Fluid

This paper deals with the preparation and complex characterization of magnetite nanoparticles (MNPs), stabilized with sodium oleate (SO), by the routine methods such as infrared spectroscopy (FTIR), magnetic measurements, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The FTIR spectra showed that SO molecules were linked to MNPs through chemical bonding. Magnetic measurements proved that the MNPs are superparamagnetic in nature. Four di erent methods were used to determine the size and size distribution of the MNPs: SEM, DLS, di erential centrifugal sedimentation (DCS) and magnetic measurements. SEM analysis showed a relatively narrow size distribution of roughly spherical MNPs with a mean diameter of 61 nm. DLS analysis con rmed monodispersed MNPs production with hydrodynamic diameter of 75 nm. The size distribution determined by DCS was found to be 69 nm. Finally, the calculated magnetic core diameter obtained from magnetization curve was 10 nm. The obtained results demonstrate that SO coated MNPs ful l the requirements for a useful drug delivery system.

Temperature Effect on Anisotropy of Acoustic Attenuation in Magnetic Fluids Based on Transformer Oil

Magnetic nanoparticles in magnetic fluids under the effect of magnetic field create structures, which are not arranged uniformly. These structures have various shapes dependent on the intensity and duration of applied magnetic field. In the case of such structures the anisotropy of acoustic attenuation can be observed. The effect of temperature on this process was studied by acoustic spectroscopy in transformer oil-based magnetic fluids. Taketomi theory that assumes existence of spherical clusters was used. These clusters form long chains, aligned in magnetic field direction. The cluster radius, the number density of the colloidal nanoparticles as well as other parameters of magnetic nanoparticles were determined from experimental results. These data allowed to draw conclusions about the changes in the parameters describing the structures of magnetic nanoparticles in the investigated magnetic fluid caused by different temperatures.

Improved the Performance of Focusing Deep Hyperthermia Inductive Heating for Breast Cancer Treatment by Using Ferro-Fluid with Magnetic Shielding System

The performance improved of focusing deep hyperthermia inductive heating for breast cancer treatment using magnetic fluid nanoparticles with magnetic shielding system has been presented in the paper and the results are discussed. It is a technique challenge in hyperthermia therapy is to control locally heat the tumor region up to an appropriate temperature to destroy cancerous cells, without damaging the surrounding healthy tissue by using magnetic fluid nanoparticles and cylindrical metal shielding with aperture. We show that the magnetic field intensity can be controlled by changing the aperture size to suitable. In addition, the position of the heating can be controlled very well with the magnetic fluid together with shielding system. In the simulation, the inductive applicator is a ferrite core with diameter of 7 cm and excited by 4 MHz signal. Results have shown that the temperature increments depend on the magnetic fluid nanoparticles. In addition, the magnetic field intensity without damaging the surrounding healthy tissue when used magnetic shielded system. These results demonstrate that it is possible to achieve higher temperatures and to focus magnetic field intensity where the nanoparticles and magnetic shielding system are used.

Visualization on the behavior of nanoparticles in magnetic fluids under the electric field

The dielectric breakdown characteristics of magnetic fluids can be influenced by the magnetic nanoparticles included because their properties should be affected by the applied electric field. Based on measuring the dielectric breakdown voltage of magnetic fluids, we found that it is higher than that of the pure transformer oil in the case of the specific volume concentrations of magnetic nanoparticles. It is known from a numerical simulation that the conductive nanoparticles might behavior as electron scavengers in the electrically stressed magnetic fluids and change fast electrons into slowly negative charged nanoparticles for the electrical breakdown. In this study, we focus on the motion of magnetic nanoparticles in the fluids under the electric field applied by the visualization using a microchannel and an optical microscope.