Magnetite Magnetic Fluids Research Articles

On the Physical–Chemical and Magnetic–Thermal Properties of Magnetite Magnetic Fluids with the Addition of Graphene

On the Physical–Chemical and Magnetic–Thermal Properties of Magnetite Magnetic Fluids with the Addition of Graphene

Effect of Graphene Flakes on the Physical and Chemical Properties of Magnetite Magnetic Fluids

Effect of Graphene Flakes on the Physical and Chemical Properties of Magnetite Magnetic Fluids

Silica anchored colloidal suspension of magnetite nanorods

This study focuses on the interaction of colloidal silica nanoparticles with the magnetite (Fe3O4) magnetic fluids (MF), which eventually forms nanorod like structure. The aqueous magnetic fluid consists of magnetite nanoparticles having double layers of lauric acid surfactant. This surfactant provides stability towards short-range van der Waals attractive and steric repulsive forces, as well as long-range dipole-dipole interactive force. Whereas, in the colloidal silica, the sodium ions provide stability to the silica nanoparticles. The colloidal silica and magnetic fluid both were mixed in different proportions to understand the interaction between the silica and magnetite nanoparticles. Thus, the interaction present in the system is studied using FTIR, TGA, and magnetic field induced microscopy. The FTIR and TGA data reveal that silica interacts with the outer layer of lauric acid through the Si–O bond and eventually provides stability to the system. The length of the lauric acid sheath varies with the concentration of silica nanoparticles. The SEM images indicate nanorod formation, and its structure dimensions vary with the silica concentrations, which is also reflected in the magnetic field-induced structure formations. The structure observed using microscopy correlated with the interaction derived from FTIR and TGA data analysis. XRD data of iron oxide (magnetite) nanoparticles are present here again for completion.

Influence of the size, shape and concentration of magnetic particles on the optical properties of nano-dispersive structures

In the present paper, using the discontinuous Ni films and magnetite magnetic fluids as examples we consider theoretically and experimentally the influence of the structural parameters on the optical properties of the ultrafine structures. The optical properties of nanostructures are represented within the theoretical Maxwell-Garnett model. The behavior of the optical spectra of thin Ni films and magnetite magnetic fluids was explained in the framework of the effective medium approximation in two cases: q < 0.5 and 0.5 < q < 1. In this model an effective refractive index (n+ik) of the nanostructures can be calculated as a function of the εm, q, and particle shapes. This approach demonstrated a good accordance between the experimental results and the theoretical calculations.

Tunable birefringence in silica mediated magnetic fluid

The present study reports magnetic and optical properties of silica mediated lauric acid stabilized magnetic fluids. The tunable birefringence (Δn) and other properties are investigated as a function of (i) concentrations of silica suspension, and (ii) saturation magnetization (MS) 0.5099 kA m−1 (FN30) and 1.2855 kA m−1 (F30) of magnetite magnetic fluid (MF). The study reveals that Δn suppresses on addition of silica in FN30, whereas enhances (up to critical concentrations of silica) in F30. The magnetic field induced chain observed in the FN30 based fluids are long, thick and scattered, while short, thin and dense chains emerges in F30 based fluid. The magnetic field induced assembly and the magnetic parameters correlates with the results of Δn. The particle size analysis indicates increment of particle size on addition of silica nanoparticles. The thermogravimetry analysis confirms the direct interaction of silica nanoparticles and the lauric acid coated magnetite particles. This is the first report of direct interaction of silica—magnetite magnetic fluids, and its subsequent effect on tunable birefringence and other properties.

Nanoprticles of metals and their inorganic compounds obtained through interphase and redox-transmetalation interaction: application in medicine and pharmacology

Synthesis of nanoparticles of metals and their compounds with given morphology and dispersity for use in medicine, pharmacology, microelectronics, as well as subsequent research of their properties, is one of the current problems in the field of preparative inorganic chemistry. Interphase synthesis and redox-transmetalation reduction are as promising as the traditional precipitation from aqueous solutions, but not as researched. This study presents the results of a physicochemical analysis of nanoparticles of metals and their compounds obtained through chemical precipitation from aqueous solutions, interphase and redox-transmetalation interaction. Data describing the influence of phase composition and dispersity of copper and copper oxide (II) nanoparticles on their antimicrobial properties, as well as the results of researching the possibility to use magnetite magnetic fluids for mesenchymal stem cells marking, illustrate the application options synthe-sized nanoparticles find in pharmacology and medicine.

Preparation and Characterization of Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; Magnetic Nanoparticles Labeled with Technetium-99m Pertectnetate

In the aspect of biomedical diagnosis, magnetic nanoparticle can be used as drug carrier and MRI/ SPECT/ PET contrast agents. Magnetic fluid hyperthermia is one of the most important cancer therapies. Magnetic nanoparticles display their unique features as heating mediators for hyperthermia. In this study, Fe3O4magnetic nanoparticle was prepared by using chemical co-precipitation method. Tc-99m pertechnetate with Fe3O4magnetic nanoparticles is prepared by using magnet adsorption method. An attempt was also made to evaluate the application in the field of magnetic targeted drug delivery and radioactive targeted cancer treatment in the future. In this work, preparation and characterization of non-polymer and polymer (dextran) coated Fe3O4magnetic nanoparticles labeled with technetium-99m pertectnetate were evaluated and served as precursors study. The Tc-99m labeling efficiency of in-house Fe3O4magnetic nanoparticles (MNP) and commercial kit were ca.98.4 % and 85% (n=5), under the same conc. of 6mM, 0.1 ml of SnCl2·2H2O, respectively. The Tc-99m labeling efficiency of magnetic nanoparticles with its dextran-coated was ca. 58.2% (n=5) at the same conc. and volume of SnCl2·2H2O. The in-vitro stabilities of the 3 kinds of magnetite magnetic fluids were higher than 96.0% (n=5) during 2 hours. The reducing agent of SnCl2·2H2O plays a key role due to its reducing ability for Tc-99m pertechnetate. The optimal reaction time of SnCl2·2H2O with Tc-99m is better under 1 hour. In conclusion, the Fe3O4magnetic nanoparticle labeled with Tc-99m pertechnetate has shown good qualities for its labeling efficiency and stability. It may be feasible preliminary to utilize in the application of magnetic targeted drug delivery of bio-medicine.

Using Chemical Coprecipitation Method to Prepare Magnetite Magnetic Fluids and Explore its Applications in Hyperthermia

Magnetic nano-particles are extensively studied in tumor therapy, target drug, gene screen, cell separation and magnetic resonance imaging study, due to theirs unique features such as its superparamagnetism, high saturation magnetization and high effective surface areas, etc. The aim of this work is to emphasize on the preparation and characterization of Fe3O4 magnetic nano-particles and its applications in hyperthermia . As the results, the Fe3O4 magnetic nanoparticle in this work has shown good qualities as well as in the literatures. It may be feasible to utilize in the field of hyperthermia.

Faraday rotation and magneto-optical figure of merit for the magnetite magnetic fluids

In the present paper, using magnetite magnetic fluids as examples, we consider the optical and magneto-optical properties of magnetic fluids based on particles of magnetic oxides, for the optical constants of the material of which, n and k , the relation 22 kn  holds. In this work the Faraday rotation is represented within the theoretical Maxwell-Garnett model. A theoretical analysis has shown that Faraday rotation for magnetic fluids is related to the Faraday rotation on the material of particles by the simple relation. According to this result in specific experimental conditions the values of the Faraday rotation prorate to q , which is the occupancy of the volume of the magnetic fluid with magnetic particles and spectral dependences of effect in magnetic fluid and in the proper bulk magnetic are similar. We also show that the values of the magneto-optical figure of merit for ultrafine medium and for the bulk material are equal.

Equatorial Kerr effect in magnetite magnetic fluids

In this research the equatorial Kerr effect is represented within the theoretical Maxwell-Garnett model. A theoretical analysis has shown that in the case of magnetic oxides, for which the condition k2 << n2 is fulfilled, the equatorial Kerr effect for magnetic fluids is related to the equatorial Kerr effect on the material of particles by the simple relation. Therefore, the amount of effect is proportional to q, which is the occupancy of the volume of the magnetic fluid with magnetic particles. Besides, the spectral dependences of magneto-optical effects are similar on the magnetic fluids and on the substance of particles. The experimental and theoretical results of the magnetite magnetic fluids are in good agreement.

The influence of dielectric permittivity of the medium on magneto-optical properties of the magnetite ultrafine structures

In our research, the influence of dielectric permittivity of the medium ϵ0on magneto-optical properties of the magnetic ultrafine structures has been evaluated on the example of the magnetite magnetic fluids. Calculations, obtained by using the correlation analyses method, showed that the influence of ϵ0 on the amount of the frequency dependences equatorial Kerr effect is 37%. We would like to underline that this result will be also suitable to all the magnetic ultrafine medium, the optical constants, n and k, of which are in relation n2 □ k2. Besides, this result gives a really good opportunity to forecast the magneto-optical properties of the ultrafine medium and therefore to receive the proper parameters of ultrafine medium.

Surface-modified magnetic nanoparticles with lecithin for applications in biomedicine

Abstract Magnetic nanoparticles were prepared by thermal decomposition and adsorbed with lecithin by applying ultrasonication. The size and saturation magnetization changes of magnetic nanoparticles were observed with different lecithin concentration, and the maximum tolerated dose (MTD) and toxicity of magnetic fluid was investigated through a biological test. As the added lecithin concentration increased in a weight loss test by heating of magnetic particles, the thickness of lecithin-adsorption layer increased non-linearly, and the proper adsorption amount was observed in the lecithin concentration of 20% (w/v). The dispersibility and magnetic property of lecithin-adsorbed magnetic nanoparticles was the most excellent when the ultrasonic holding time was 1.5 h. Also, the maximum tolerated concentration with best cell viability was 32 μg/ml by in vitro test, and lecithin-adsorbed magnetic fluids showed the improved biocompatibility by 1.2 times compared with pure magnetite magnetic fluids.

Spin-glass-like magnetic ordering in Zn substituted magnetite magnetic fluids

Electron spin resonance (ESR) spectra of magnetic fluids involving polydispersed Zn 0.5Fe 0. 5Fe 2O 4 (FZ5) and Zn 0.7Fe 0. 3Fe 2O 4 (FZ7) nanomagnetic particles are scanned from 4.2 to 300 K. The FZ7 fluid exhibits certain distinct features below 40 K which are different from FZ5 fluid. These include (i) an isotropic shift in resonance field in zero-field-cooled ESR study, (ii) deviation of resonance field from sin 2 θ behavior (where θ is the angle between axis of the particle and field) in field cooled (FC) sample and (iii) abrupt increase in anisotropy field for FC sample. The results are analyzed in light of the core-shell model for nanomagnetic particles.

Core-shell structure and magnetic properties of magnetite magnetic fluids stabilized with dextran

The adsorption process of different dextran molecules onto the surface of in water dispersed magnetite nanoparticles has been investigated to optimize the preparation of magnetite magnetic fluids (MMFs). An average magnetite core size of 7.1 nm was found by X-ray diffraction and that of 8 nm was found by transmission electron microscopy for the samples prepared at 90 °C. An average hydrodynamic diameter of 25 nm was observed by scanning electron microscopy and that of 25–300 nm was obtained by photon correlation spectroscopy. The dextran was adsorbed by physical adsorption, a molecular weight of 20 kDa gave the best stability of these MMFs. The shell layer of the particles was weakly negatively charged in buffer solutions of pH values between 5.5 and 9.5. The particles seem to be mainly stabilized by sterical repulsion. The maximum available saturation magnetization of the MMFs was 3.5 kA/m.

Aqueous-based magnetite magnetic fluids stabilized by surface small micelles of oleolysarcosine

The adsorption of N-oleoylsarcosine onto in water dispersed magnetite nanoparticles were investigated at different concentrations and pH values. The coated nanoparticles surface became hydrophobic at a molar ratio of N-oleoylsarcosine:Fe 3O 4 below 0.22:1 within a pH range of 5–9.5. Aqueous-based magnetic fluids could not be obtained. A hydrophilic surface was observed at a molar ratio of N-oleoylsarcosine:Fe 3O 4 above 0.37:1 and at pH levels ranging from 6 to 8.5. Stable aqueous-based magnetic fluids could be prepared. The magnetite particles flocculate at pH levels below 5.5 or above 8.5. The hydrophobic behavior was explained assuming a monolayer adsorption mode. On the other hand, the hydrophilic properties were caused by a bilayer adsorption structure. This hypothesis was in overestimation with results of infrared (IR) spectroscopy and photon correlation spectroscopy of the prepared magnetic fluids. The influences of pH levels on the formation of N-oleoylsarcosine micelles were also discussed to explain the pH-dependant formation of bilayer adsorption structure, i.e. surface small micelle structure. It was indicated that it became difficult for N-oleoylsarcosine adsorb at the water–air interface, or adsorb at the nanoparticles surfaces in the form of surface small micelles at pH levels above 8.5. Besides, the aqueous-based magnetic fluids were also characterized by magnetization curve determinations.

Interaction of superparamagnetic and non-superparamagnetic particles in magnetic fluid

Magnetic fluids are known to contain superparamagnetic and non-superparamagnetic particles. In this paper, an attempt has been made to show the interaction between superparamagnetic and non-superparamagnetic particles experimentally by measuring the initial susceptibility, over a wide temperature range, of manganese-zinc ferrite and cobalt ferrite magnetic fluids both separate and as mixtures. Likewise experiments were done with manganese-zinc ferrite and magnetite magnetic fluids. The results showed that when the percentage of non-superparamagnetic particles is high, the interaction is high when the particle rotations are restricted. The interaction was less for the system where the non-superparamagnetic particle fraction is small, as in the case of manganese-zinc ferrite and magnetite mixture. The above was true for both zero field cooled and field cooled cases.

Rheological properties of magnetite magnetic fluid

The magnetic and rheological properties of magnetite magnetic fluids of different concentrations and dispersions have been investigated. The dispersion of the samples was varied in magnetite precipitation stage as well as by using HGMS. Like the concentration, the fluid dispersion also affects the rheological properties in an applied field.