Aqueous magnetic fluids stabilized by surfactant bilayers

Shen, Lifen; Laibinis, Paul E.; Hatton, T. Alan

doi:10.1016/s0304-8853(98)00587-3

Cited by 60 publications

(33 citation statements)

References 13 publications

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“…Thus, fatty acid C-12 (lauric acid) is most suitable for water-base ferrofluids [19]. There are several research papers, which describe the arrangement of fatty acid molecules on the magnetite nanoparticle [19][20][21]. In brief, the fatty acid molecules are arranged in bilayer fashion, namely, primary and secondary layers.…”

Section: In Vitro Cytocompatibility Studymentioning

confidence: 99%

Synthesis and characterizations of water-based ferrofluids of substituted ferrites [Fe1−xBxFe2O4, B=Mn, Co (x=0–1)] for biomedical applications

Giri

Pradhan

Somani

et al. 2008

Journal of Magnetism and Magnetic Materials

113

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Section: In Vitro Cytocompatibility Studymentioning

confidence: 99%

Synthesis and characterizations of water-based ferrofluids of substituted ferrites [Fe1−xBxFe2O4, B=Mn, Co (x=0–1)] for biomedical applications

Giri

Pradhan

Somani

et al. 2008

Journal of Magnetism and Magnetic Materials

113

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“…1 Since their discovery in 1965 by Papell, 2 ferrofluids have raised a growing interest in the scientific and industrial communities due to their physical properties and applications. Ferrofluids can be applied to immunoassay, cell separation, contrast agents for ultrasound and magnetic resonance imaging (MRI), magnetic inks, biosensors, magnetic microactuactors, seals, bearing dampers and lubricants, etc.…”

Section: Introductionmentioning

confidence: 99%

Preparation of a ferrofluid using cyclodextrin and magnetite

Bocanegra-Diaz¹,

Mohallem²,

Sinisterra³

2003

J. Braz. Chem. Soc.

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Um ferrofluido foi obtido a partir da magnetita e da β-ciclodextrina, com a formação de um complexo de inclusão. A caracterização físico-química do complexo magnétita: β-ciclodextrina foi realizada através de espectroscopia de absorção na região do infravermelho com transformada de Fourier, difração de raios X, análise térmica (TG/DTA), microscopia eletrônica de transmissão (TEM) e espectroscopia de absorção atômica. É a primeira vez que se relata na literatura a formação de um complexo de inclusão de um óxido metálico em ciclodextrinas A ferrofluid has been obtained from magnetite and β-cyclodextrin, with the formation of an inclusion complex. The magnetite and β-cyclodextrin complex was characterized by FTIR spectroscopy, X-ray diffraction, thermal analysis (TG/DTA), transmission electron microscopy (TEM) and atomic absorption spectroscopy. As far as we know, this is the first report on an inclusion compound between a metal oxide and cyclodextrins. Keywords: ferrofluid, cyclodextrin, magnetite, magnetic materials, inclusion complex IntroductionFerrofluids are colloidal suspensions composed of single-domain magnetic nanoparticles dispersed in appropriate solvents (polar or non polar).1 Since their discovery in 1965 by Papell, 2 ferrofluids have raised a growing interest in the scientific and industrial communities due to their physical properties and applications. Ferrofluids can be applied to immunoassay, cell separation, contrast agents for ultrasound and magnetic resonance imaging (MRI), magnetic inks, biosensors, magnetic microactuactors, seals, bearing dampers and lubricants, etc. 3These specialized applications of ferrofluids impose strict requirements on their characteristics, such as chemical composition, size distribution uniformity, crystal structure, stability of magnetic properties, surface structure, adsorption properties, solubility and low toxicity. Many of these properties depend decisively on particle size, shape, composition and structure, and therefore rigorous control of the synthesis of ferrofluids is necessary. 5Cyclodextrins are water-soluble oligosaccharides composed of at least six (1-4) linked α-D-glucosyl residues which have the shape of a hollow, truncated cone, capable of forming inclusion complexes with a variety of guest molecules in the solid state, as well as in solution, with sizes compatible with the dimensions of the cavity. 7Cyclodextrins are used as surfactants and size controllers of different kind of materials. 6In the present work, we describe the preparation and characterization of a ferrofluid using β-cyclodextrin to stabilize magnetite nanoparticles in colloidal suspension. In this system, β-cyclodextrin may also act as a size selector. ExperimentalAnalytical grade chemicals and deionized water were used throughout. Synthesis of magnetite Preparation of the magnetic fluidThe preparation of the magnetic fluid was carried out by mixing 2.8 mg of β-cyclodextrin and 8.0 mL of NH 4 OH (8.5 mol L -1 ) dissolved in 15.0 mL of deionized water under continuous and vigorous st...

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“…Recently, SANS data obtained from surfactant bilayer-stabilized Fe 2 O 3 nanoparticles [23], analysed through an interparticle structure factor described by a fractal model, suggested that these S-MF form lose clusters of about 4 to 8 particles having correlation lengths of approximately 300Å.…”

Section: Discussionmentioning

confidence: 99%

Nanoparticle chain-like formation in electrical double-layered magnetic fluids evidenced by small-angle X-ray scattering

Itri

Depeyrot

Tourinho

et al. 2001

The European Physical Journal E

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Small-angle X-ray scattering (SAXS) was performed on a series of Electric Double-Layered Magnetic Fluids (EDL-MF) composed of ferrite type-CoFe2O4, MnFe2O4, ZnFe2O4, NiFe2O4 and CuFe2O4-nanoparticles of different crystalline sizes (DXR ranging from 40 to 139Å, as determined by X-ray diffraction). The information concerning the scattering objects was obtained through the analysis of the distance distribution function p(r) and of the size distribution function D(R), both retrieved from SAXS data. The results show that EDL-MF, in the absence of an applied magnetic field, are composed of small magnetic particle aggregates in solution. These agglomerates are elongated in one direction (chain-like) with the longest dimension varying from 240 to 330Å. The cross-section size is of the order of D XR. The data also demonstrate that the maximum dimension of these aggregates is independent of the ferrite type. On the other hand, the number of aggregated magnetic particles is nanoparticle-size-dependent. Accordingly, larger ferrite-type nanoparticles as those with D XR = 139Å form aggregates composed of 2-3 magnetic particles, whereas smaller ones with DXR ∼ = 40Å form agglomerates of about 6 magnetic particles in solution. As the nanoparticle size is reduced, it might increase the particle surface defects. Such occurrence would affect the particle surface charge density, which could reduce the electrostatic screening, favoring the agglomeration phenomenon.PACS. 75.50.Mm Magnetic liquids -75.50.Tt Fine-particle systems -61.10.Eq X-ray scattering (including small-angle scattering)

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Aqueous magnetic fluids stabilized by surfactant bilayers

Cited by 60 publications

References 13 publications

Synthesis and characterizations of water-based ferrofluids of substituted ferrites [Fe1−xBxFe2O4, B=Mn, Co (x=0–1)] for biomedical applications

Synthesis and characterizations of water-based ferrofluids of substituted ferrites [Fe1−xBxFe2O4, B=Mn, Co (x=0–1)] for biomedical applications

Preparation of a ferrofluid using cyclodextrin and magnetite

Nanoparticle chain-like formation in electrical double-layered magnetic fluids evidenced by small-angle X-ray scattering

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