Surface oxidation, size and shape of nano-sized magnetite obtained by co-precipitation

Nedkov, I.; Merodiiska, T.; Slavov, L.; Vandenberghe, R. E.; Kusano, Yoshihiro; Takada, Jun

doi:10.1016/j.jmmm.2005.05.020

Cited by 126 publications

(80 citation statements)

References 8 publications

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“…Another possibility is that this central part of the 80 K spectrum is due to some superparamagnetic magnetite, reinforced by the isomer shift value of 0.34 mm/s which is typical for Fe 3 + (see Table 3) and not for iron clusters in the foil. In our previous investigation based on Mössbauer measurements, we showed that the surface of magnetite nanoparticles has a defective structure spanning around 30% of its volume [31,14]. The investigations made in this paper reinforce this assumption with the Raman micro-spectroscopy being able to distinguish clearly a stoichiometric magnetite as a main phase in the ferrofluids.…”

Section: Resultssupporting

confidence: 77%

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Raman spectroscopy investigation of magnetite nanoparticles in ferrofluids

Slavov

Abrashev

Merodiiska

et al. 2010

Journal of Magnetism and Magnetic Materials

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222

107

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a b s t r a c tRaman spectroscopy is used to investigate magnetite nanoparticles dispersed in two types of bcyclodextrin suspensions. An approach is presented for characterization of the magnetic core in liquid surrounding at room temperature and atmospheric pressure. The effect of elevating laser power on the structural stability and chemical composition of magnetite in the ferrofluids is discussed. The data are compared with data from dry by-products from the fluids. Powder samples undergo total phase transition from magnetite to hematite at laser power of 1.95 mW. The same nanoparticles in the fluid undergo transformation at 9 mW, but no hematite positions appear throughout that investigation. The Raman spectra revealed that the main phase of the magnetic core in the fluids is magnetite. That is indicated by a strong and non-diminishing in intensity peak at 670 cm. A second phase is present at the nanoparticle's surface with Raman spectroscopy unveiling maghemite-like and small fractions of goethite-like structures. The Fourier transform infrared spectroscopy investigations confirm deviations in the surface structure and also point to the fact that the oxidation process starts at an early stage after formation of the nanoparticles. The analyses of the infrared data also show that b-cyclodextrin molecules retain their cyclic character and the coating does not affect the oxidation process once the particles are evicted from the fluids. A Mössbauer spectroscopy measurement on a ferrofluidic sample is also presented.

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Section: Resultssupporting

confidence: 77%

“…The aim of the investigation was to obtain new information about the development towards a second, maghemite-like phase on the surface of magnetite nanoparticles [14], when dispersed in liquid using Raman spectroscopy. The role of the liquid surrounding for reducing or preventing such development was also studied.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy investigation of magnetite nanoparticles in ferrofluids

Slavov

Abrashev

Merodiiska

et al. 2010

Journal of Magnetism and Magnetic Materials

Self Cite

222

107

View full text Add to dashboard Cite

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“…Among the chemical routes used so far to synthesize iron oxide based nanomaterials, it is worth to mention hydrothermal synthesis [15,16], coprecipitation [17], solgel method [18], and colloidal chemistry method [19]. These methods usually involve synthesizing an iron-based precursor gel, followed by decomposing the gel or precursor into the designed crystalline iron oxide phase at an elevated temperature.…”

Section: Introductionmentioning

confidence: 99%

Ultrafine Magnetite Nanopowder: Synthesis, Characterization, and Preliminary Use as Filler of Polymethylmethacrylate Nanocomposites

Russo

Acierno

Palomba

et al. 2012

Journal of Nanotechnology

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Magnetite (Fe 3 O 4 ) nanoparticles prepared by microwave-assisted hydrothermal synthesis have been characterized in terms of morphological and structural features. Electron micrographs collected in both scanning (SEM) and transmission (TEM) modes and evaluations of X-ray powder diffraction (XRD) patterns have indicated the achievement of a monodispersed crystallite structure with particles having an average size around 15-20 nm. Structural investigations by Micro-Raman spectroscopy highlighted the obtainment of magnetite nanocrystals with a partial surface oxidation to maghemite (γ-Fe 3 O 4 ). Preliminary attention has been also paid to the use of these magnetite nanoparticles as filler for a commercial polymethylmethacrylate resin. Hybrid formulations containing up to 3 wt% of nanoparticles were prepared by melt blending and characterized by calorimetric and thermogravimetric tests. For sake of comparison, same formulations containing commercial Fe 3 O 4 nanoparticles are also reported. Calorimetric characterization indicates an increase of both glass transition temperature and thermal stability of the nanocomposite systems when loaded with the synthesized magnetite nanoparticles rather then loaded with the same amount of commercial Fe 3 O 4 . This first observation represents just one aspect of the promising potentiality offered by the novel magnetic nanoparticles when mixed with PMMA.

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“…It can be achieved with the systems, which are associated with external or feed back control such as magnetic control [4] . Magnetically targeted drug delivery system (MT-DDS) will be a promising way, which involves binding a drug to a small biocompatible magnetically active component, entrapped in the biodegradable polymeric matrix and formulating in to a pharmacologically active stable formulation, which is injected into the blood stream and using a high-gradient magnetic field to pull them out of suspension in the target region [5][6][7] . Magnetic microspheres will be formulated with an intension to produce a depot near the target organ, by placing a suitable magnet near it.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Magnetic Methyl Methacrylate Microspheres Loaded with Indomethacin by Emulsion Solvent Evaporation Technique.

Varma¹,

Amareshwar²,

Devara³

2011

Int J Drug Del

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Magnetic nanoparticles encapsulated in Methyl methacrylate (Eudragit L-100) microspheres containing Indomethacin drug were prepared and their detailed structural and magnetic characteristics were studied. Iron oxide nanoparticles were obtained by chemical coprecipitation of Fe(II) and Fe(III) salts and stabilized with tetra-methyl ammonium hydroxide. Microspheres were prepared by solvent evaporation technique. We characterized the magnetic microspheres in terms of morphology, composite microstructure, size and size distribution, magnetic properties and in-vitro release patterns. The microspheres were uniform both in shape and usually also in size; their size distribution was narrow. All the magnetic parameters confirm superparamagnetic nature of the microspheres with magnetizations up to 20-30 emu/g of microspheres. The in-vitro release profile was studied in pH 7.4 phosphate buffer medium up to 8 hours using USP XXII dissolution apparatus. Drug release in the first hour was found to increase and reached a maximum, releasing approximately 60-85% of the total drug content from the microspheres within 8 hours. From this study, it could be suggested that magnetic Methyl methacrylate microspheres could be retained at their target site invivo and such microspheres can be used in biomedical applications and research areas such as target drug delivery, selective blood detoxification, tissue engineering and replacement, and magnetic resonance imaging (MRI) contrast agents.

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Surface oxidation, size and shape of nano-sized magnetite obtained by co-precipitation

Cited by 126 publications

References 8 publications

Raman spectroscopy investigation of magnetite nanoparticles in ferrofluids

Raman spectroscopy investigation of magnetite nanoparticles in ferrofluids

Ultrafine Magnetite Nanopowder: Synthesis, Characterization, and Preliminary Use as Filler of Polymethylmethacrylate Nanocomposites

Synthesis and Characterization of Magnetic Methyl Methacrylate Microspheres Loaded with Indomethacin by Emulsion Solvent Evaporation Technique.

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