Surface charge density determination in electric double layered magnetic fluids

Tourinho, F.A.; Campos, Alex Fabiano Cortez; Aquino, Renata; Lara, M.C.F.L.; Silva, G. J. da; Depeyrot, J.

doi:10.1590/s0103-97332002000300008

Cited by 30 publications

(21 citation statements)

References 9 publications

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“…magnetite (Fe 3 O 4 ), having diameters in the nanometric scale are known as magnetic fluids (MFs) or ferrofluids (see Ref. [2] and references therein). In the last decade MFs have been used in several fields, especially in medicine and biosciences [3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Surface-enhanced Raman spectra of magnetic nanoparticles adsorbed on a silver electrode

Jacintho

Cório

Rubim

2007

Journal of Electroanalytical Chemistry

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Section: Introductionmentioning

confidence: 99%

Surface-enhanced Raman spectra of magnetic nanoparticles adsorbed on a silver electrode

Jacintho

Cório

Rubim

2007

Journal of Electroanalytical Chemistry

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“…Ferrofluids are a type of magnetic fluid consisting typically of colloidal magnetic particles such as magnetite 1 or other ferrites with spinel structures presenting the [M II Fe 2 O 4 ] general formula, where M can be one of the following transition metals: Zn, Co, Cu, Mn, Ni and Fe. 2,3 The magnetic particles have average diameters ranging from 3 to 10 nm 2 and are usually dispersed in a continuous carrier.…”

Section: Introductionmentioning

confidence: 99%

“…Depending on the way in which the dispersion of the particles in the carrier is promoted, e.g. by the use of surfactants, one obtains ferrofluids that are useful for aprotic solvents, or by the use of an oxidation step where iron(III) nitrate is involved one produces the electric double layered ferrofluids (edl-ff) 1 which are suitable for aqueous solution. Each particle has a constant magnetic dipole moment proportional to its size.…”

Section: Introductionmentioning

confidence: 99%

Use of Raman micro-spectroscopy in the characterization of MIIFe2O4 (M = Fe, Zn) electric double layer ferrofluids

Tourinho

Rubim

2000

J. Raman Spectrosc.

111

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M II Fe 2 O 4 (M = Fe, Zn) electric double layer ferrofluids (edl-ferrofluids) were investigated and characterized by Raman micro-spectroscopy as solids (powder) or in solution forming magnetic fluids. The Raman spectra showed that the nanoparticles forming the magnetic fluids have different compositions depending on the M II ion used in their preparation. In the case of FeFe 2 O 4 edl-ferrofluid, maghemite, magnetite, an amorphous non-stoichiometric oxyhydroxide [FeO x (OH) 3−2x , x < 1] and Fe(OH) 3 phases are present. In the case of the ZnFe 2 O 4 edl-ferrofluid, a magnetite-like structure where the Fe II centers were replaced by the Zn II ions is present. A model of the distribution of the different chemical phases on the nanoparticles is presented. The Raman spectrum of the FeFe 2 O 4 edl-ferrofluid excited close to an absorption band of the sample at 650 nm presents several Raman features above 900 cm −1 that are not observed for the ZnFe 2 O 4 edl-ferrofluid sample. These results have been interpreted considering the resonant excitation of the density of phonon states with k 6 = 0 due to quantum size effects.

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“…Electric Double-Layered magnetic fluids (EDL-MF) are ultrastable colloidal suspensions of magnetic ferrite particles electrostatically dispersed in water [1]. Besides their interest for the fundamental research [2], EDL-MFs are precursors of biocompatible magnetic fluids, where coated magnetic nanoparticles can be used for drug vectoring, cell sorting and oncological treatment [3].…”

Section: Introductionmentioning

confidence: 99%

Nanoparticles superficial density of charge in electric double-layered magnetic fluid: A conductimetric and potentiometric approach

Campos

Tourinho

Silva

et al. 2001

The European Physical Journal E

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We analyze potentiometric and conductimetric measurements simultaneously performed on Electric Double-Layer Magnetic Fluid based on cobalt ferrite nanoparticles, in order to obtain the pHdependence of the particle surface charge density. We propose a mechanism for the charging of the particle surface. This model considers the ferrofluid solution as a mixture of strong and weak diprotic acids. We show how an exact analytical treatment involving proton transfer between the particle surface and the bulk solution allows the construction of a speciation diagram of the charged superficial sites. The saturation value of the superficial density of charge is found to be equal to 0.326 ± 0.065 C m −2 .

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Surface charge density determination in electric double layered magnetic fluids

Cited by 30 publications

References 9 publications

Surface-enhanced Raman spectra of magnetic nanoparticles adsorbed on a silver electrode

Surface-enhanced Raman spectra of magnetic nanoparticles adsorbed on a silver electrode

Use of Raman micro-spectroscopy in the characterization of MIIFe2O4 (M = Fe, Zn) electric double layer ferrofluids

Nanoparticles superficial density of charge in electric double-layered magnetic fluid: A conductimetric and potentiometric approach

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