Air-stable Co-, Fe-, and Fe/Co-Nanoparticles and Ferrofluids
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Silke Behrens
Summary
Air-stable Co, Fe, and Fe/Co nanoparticles are accessible by thermolysis of the metal carbonyl precursors in the presence of aluminium alkyls and subsequent “smooth oxidation”. The structure of the particles was investigated by transmission electron microscopy (TEM, HRTEM), X-ray absorption spectroscopy (XAS), X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS), metastable impact electron spectroscopy (MIES), and small-angle neutron scattering (SANS). The peptization of the nanoparticles with suitable surfactants (oleic and lauric acid, sodium dioctylsulfosuccinate (AOT), LP-4 (a fatty acid condensation polymer), and KorantinSH (N-oleyl sarcosine)) yields magnetic fluids dispersed in carrier liquids such as toluene, kerosene, vacuum and mineral oils which are remarkably stable in air under ambient conditions. The resulting magnetic fluids show good magnetic properties. Several methods for the preparation of water-based MF are presented, e.g., formation of surfactant bilayers, using phase transfer agents, or surface modification with L-cysteine ethyl ester. Water-based metallic magnetic fluids have a high potential for a number of technical and biomedical applications. Technical applications of the Co-based ferrofluids in the field of positioning systems and magnetohydrostatic bearings were investigated. The results emphasize the scope of nanoparticulate ferrofluids having a metallic core.
© by Oldenbourg Wissenschaftsverlag, München
Articles in the same Issue
- Preface. 88th International Bunsen Discussion Meeting – 6th German Ferrofluid Workshop: “Magnetic Colloidal Fluids: Preparation, Characterization, Physical Properties and Applications”
- Air-stable Co-, Fe-, and Fe/Co-Nanoparticles and Ferrofluids
- Magnetic Polymer Brushes: Towards Tailor-Made Stabilization of Magnetic Fluids by Surface-Initiated Polymerization
- Precipitated Iron Oxide Particles by Cyclic Growth
- Production and Characterisation of Ferromagnetic Nanoscale Metal Powders Produced by Laser Evaporation
- Dependence of Brownian Relaxation on the Volume Fraction and an External Field
- NMR-Characterization of Magnetic Fluids
- Periodically Forced Ferrofluid Pendulum: Effect of Polydispersity
- Surface Waves and Rosensweig Instability in Isotropic Ferrogels
- Polydispersity Influence upon Magnetic Properties of Aggregated Ferrofluids
- Magnetic Fluid Layer on a Cylinder in a Traveling Magnetic Field
- The Carboxymethyl Dextran Shell is an Important Modulator of Magnetic Nanoparticle Uptake in Human Cells
- A Successful Strategy for the Production of Cationic Magnetoliposomes
Articles in the same Issue
- Preface. 88th International Bunsen Discussion Meeting – 6th German Ferrofluid Workshop: “Magnetic Colloidal Fluids: Preparation, Characterization, Physical Properties and Applications”
- Air-stable Co-, Fe-, and Fe/Co-Nanoparticles and Ferrofluids
- Magnetic Polymer Brushes: Towards Tailor-Made Stabilization of Magnetic Fluids by Surface-Initiated Polymerization
- Precipitated Iron Oxide Particles by Cyclic Growth
- Production and Characterisation of Ferromagnetic Nanoscale Metal Powders Produced by Laser Evaporation
- Dependence of Brownian Relaxation on the Volume Fraction and an External Field
- NMR-Characterization of Magnetic Fluids
- Periodically Forced Ferrofluid Pendulum: Effect of Polydispersity
- Surface Waves and Rosensweig Instability in Isotropic Ferrogels
- Polydispersity Influence upon Magnetic Properties of Aggregated Ferrofluids
- Magnetic Fluid Layer on a Cylinder in a Traveling Magnetic Field
- The Carboxymethyl Dextran Shell is an Important Modulator of Magnetic Nanoparticle Uptake in Human Cells
- A Successful Strategy for the Production of Cationic Magnetoliposomes
