Sterically stabilized water based magnetic fluids: Synthesis, structure and properties (original) (raw)
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Nanomaterials
The present work reports the synthesis of a stable aqueous magnetic fluid (AMF) by dispersing double-surfactant-coated Fe3O4 magnetic nanoparticles (MNPs) in water using a facile ambient scalable wet chemical route. MNPs do not disperse well in water, resulting in low stability. This was improved by dispersing double-surfactant (oleic acid and sodium oleate)-coated MNPs in water, where cross-linking between the surfactants improves the stability of the AMFs. The stability was probed by rheological measurements and all the AMF samples showed a good long-term stability and stability against a gradient magnetic field. Further, the microwave spin resonance behavior of AMFs was studied in detail by corroborating the experimental results obtained from the ferromagnetic resonance (FMR) technique to theoretical predictions by appropriate fittings. A broad spectrum was perceived for AMFs which indicates strong ferromagnetic characteristics. The resonance field shifted to higher magnetic fiel...
Water-soluble magnetic nanoparticles with biologically active stabilizers
Journal of Magnetism and Magnetic Materials, 2009
We present the results of the interaction of iron oxide nanoparticles with some biologically active surfactants, namely, oleic acid and cytotoxic alkanolamine derivatives. Physico-chemical properties, as magnetization, magnetite concentration and particle diameter, of the prepared magnetic samples were studied. The nanoparticle size of 11 nm for toluene magnetic fluid determined by TEM is in good agreement with the data obtained by the method of magnetogranulometry. In vitro cytotoxic effect of water-soluble nanoparticles with different iron oxide:oleic acid molar ratio were revealed against human fibrosarcoma and mouse hepatoma cells. In vivo results using a sarcoma mouse model showed observable antitumor action.
Studies of the double surfactant layer stabilization of water-based magnetic fluids
Journal of colloid and interface …, 1991
A comparison of the ability of C6-Cj8 carboxylic acids to stabilize aqueous magnetite fluids is made. Micelle formation prevented complete dispersion of magnetite by stearic and myristic acids, but was overcome by introducing the acid in several portions. Improvements in fluid preparation are reported, achieved by perchloric acid treatment of surfactant-stabilized magnetite produced in basic solution, followed by redispersion of the particles in dilute base. The quantity of surfactant in the primary layer has been determined for C~0-Cl8 acids, and the particle surface area occupied per molecule of surfactant found to range between ca. 21 and 38 ~2. For decanoic and myristic acids the groups pack efficiently and form a "condensed" film over the surface of the particles. Ammonium and monomethylammonium salts of the same acids were used in attempts to form the secondary layers. Ammonium salts produced dispersion in all cases except Sarkosyl-"O," whereas MeNH~ salts of oleic and myristic acids were successful. Quantitative data on the relative amounts of surfactant in each layer are presented and discussed.
Citric-acid-coated magnetite nanoparticles for biological applications
European Physical Journal E, 2006
Water-based magnetic fluids, generally intended for biomedical applications, often have various coating molecules that make them stable and compatible with biological liquids. Magnetic fluids containing iron oxide particles have been prepared by a co-precipitation method, using citric acid as stabilizer. The magnetic particles of the magnetic fluids were obtained by chemical precipitation from ferric ( FeCl3) and ferrous salts ( FeSO4 or FeCl2) in alkali medium (ammonia hydroxide). Citric acid was used to stabilize the magnetic-particle suspension. Physical tests were performed in order to determine various microstructural and rheological features. Transmission electron microscopy was the main investigation method for assessing the magnetic-particle size. The dimensional distribution of the magnetic-particle physical diameter was analyzed using the box-plot statistical method while infrared absorption spectra were used to study the colloidal particle structure. The magnetic-fluid density (picnometric method), viscosity (capillary method) and surface tension (stalagmometric method) were measured using standard methods.
Rheological Study of Dextran-Modified Magnetite Nanoparticle Water Suspension
International Journal of Thermophysics, 2013
The aim of this work is to investigate the effect of surface modification of superparamagnetic magnetite nanoparticles (sterically stabilized by sodium oleate) by the dextran biocompatible layer on the rheological behavior of water-based magnetic fluids. The flow curves were measured as a function of the magnetic field strength by means of rheometry. The measured viscosity is generally dependent on both the particle concentration and the geometrical factors such as the particle shape and thickness of the adsorbed layers. The rheological properties of the magnetic fluids studied show the effect of the magnetic field strength and the presence of the surfactant second layer (dextran) on their viscosity. Keywords Fluid flow • Magnetic fluid • Nanoparticles • Rheological properties 1 Introduction Iron oxide nanoparticles are being developed for a wide range of biomedicine applications and diagnostics (magnetic drug targeting, magnetic hyperthermia, MRI contrast
179 New magnetic fluid developed with natural organic compounds biocompatible.
This work was developed with an aqueous suspension of maghemite nanoparticles and colloidal emulsions with nanoparticles of magnetite. The nanoparticles were synthesized by co-precipitation method. The first was the magnetic emulsion nanoparticles of maghemite dispersed in the aqueous extract obtained from the leaf embauba (Cecropia Obtusifolia), whose tree is native to Central and South America. Thereby achieving the magnetic fluid extract embauba stabilized with ionic buffer solution pH 7.4. A second emulsion was prepared with colloidal magnetite nanoparticles with surfaces previously coated with oleic acid as a means of dispersing and using the oil extracted from in nature seed Andiroba (Carapa Guianensis), tree of the Brazilian Amazon. These new magnetic fluids the nanoparticles were characterized by Photoacoustic spectroscopy (PAS) to determine the coating layer of molecules on the surfaces of nanoparticles. In aqueous ionic magnetic fluid Cecropia Obtusifolia (MFCO) chlorogenic acid contributes to the electron density in the presence of four groups alcohols, a ketone group and a carboxylic group. In magnetic fluid-based oil andiroba MFAD PAS spectra show that oleic acid molecules are tightly linked on the surface of the nanoparticles.
New Magnetic Fluid Developed with Natural Organic Compounds Biocompatible
Journal of Nanoscience and Nanotechnology, 2012
This work was developed with an aqueous suspension of maghemite nanoparticles and colloidal emulsions with nanoparticles of magnetite. The nanoparticles were synthesized by co-precipitation method. The first was the magnetic emulsion nanoparticles of maghemite dispersed in the aqueous extract obtained from the leaf embauba (Cecropia Obtusifolia), whose tree is native to Central and South America. Thereby achieving the magnetic fluid extract embauba stabilized with ionic buffer solution pH 7.4. A second emulsion was prepared with colloidal magnetite nanoparticles with surfaces previously coated with oleic acid as a means of dispersing and using the oil extracted from in nature seed Andiroba (Carapa Guianensis), tree of the Brazilian Amazon. These new magnetic fluids the nanoparticles were characterized by Photoacoustic spectroscopy (PAS) to determine the coating layer of molecules on the surfaces of nanoparticles. In aqueous ionic magnetic fluid Cecropia Obtusifolia (MFCO) chlorogenic acid contributes to the electron density in the presence of four groups alcohols, a ketone group and a carboxylic group. In magnetic fluid-based oil andiroba MFAD PAS spectra show that oleic acid molecules are tightly linked on the surface of the nanoparticles.
Magnetoviscosity and wettability of magnetic fluids containing magnetite nanocubes
2019
Magnetic fluid Magnetite Nanocube Viscosity Contact Angle Magnetic fluids have been widely implemented in engineering and biomedical applications due to their tuneable rheology and magnetization. In this paper, magnetite (Fe3O4) dispersed in hexane are investigated. Synthesized by the reduction of ferric acetylacetonate, nanoparticles including nanocubes are obtained with the average size of 13.7 nm. Their dispersion only slightly modifies the wettability and viscosity of hexane. By contrast, the viscosity of the magnetic fluid is significantly increased from 0.284 to 0.339 cP when the U-tube viscometer was subjected to 142 Oe magnetic field from an electromagnet. This magnetoviscosity is attributed to the interaction between nanoparticles in response to the applied magnetic field. The adjustment of fluid flow by magnetic field can be utilized in nanolubrication and bearing.
2012
Magnetite nanoparticles (MNPs) coated with poly(acrylic acid-co-maleic acid) polyelectrolyte (PAM) have been prepared with the aim of improving colloidal stability of core−shell nanoparticles for biomedical applications and enhancing the durability of the coating shells. FTIR-ATR measurements reveal two types of interaction of PAM with MNPs: hydrogen bonding and inner-sphere metal−carboxylate complex formation. The mechanism of the latter is ligand exchange between uncharged −OH groups of the surface and −COO − anionic moieties of the polyelectrolyte as revealed by adsorption and electrokinetic experiments. The aqueous dispersion of PAM@MNP particles (magnetic fluids − MFs) tolerates physiological salt concentration at composition corresponding to the plateau of the high-affinity adsorption isotherm. The plateau is reached at small amount of added PAM and at low concentration of nonadsorbed PAM, making PAM highly efficient for coating MNPs. The adsorbed PAM layer is not desorbed during dilution. The performance of the PAM shell is superior to that of poly(acrylic acid) (PAA), often used in biocompatible MFs. This is explained by the different adsorption mechanisms; metal−carboxylate cannot form in the case of PAA. Molecularlevel understanding of the protective shell formation on MNPs presented here improves fundamentally the colloidal techniques used in core−shell nanoparticle production for nanotechnology applications.