Abstract: Hermetically Coated Superparamagnetic Fe2O3 Particles with SiO2 Nanofilms (2009 Annual Meeting)

Thursday, November 12, 2009: 9:42 AM

Delta Ballroom D (Gaylord Opryland Hotel)

Alexandra Teleki, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland

Marcel Suter, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich, Micro- and Nanosystems, Zurich, Switzerland

Piran R. Kidambi, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland

Olgac Ergeneman, Department of Mechanical and Process Engineering, ETH Zurich, Institute of Robotics and Intelligent Systems, Zurich, Switzerland

Frank Krumeich, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland

Bradley J. Nelson, Department of Mechanical and Process Engineering, ETH Zurich, Institute of Robotics and Intelligent Systems, Zurich, Switzerland

Sotiris E. Pratsinis, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland

Magnetic nanoparticles are frequently coated with SiO₂ to improve their functionality and bio-compatibility in a range of biomedical and polymer nanocomposite applications. Here, a scalable flame aerosol technology is used to produce highly dispersible, superparamagnetic iron oxide nanoparticles hermetically coated with silica to retain full magnetization performance.^[1] Iron oxide particles were produced by flame spray pyrolysis (FSP) of iron acetylacetonate in xylene/acetonitrile solutions and the resulting aerosol was in-situ coated with silicon dioxide by oxidation of swirling hexamethlydisiloxane vapor.^[2] The process allows independent control of the core Fe₂O₃ (maghemite) particle properties and the thickness of their silica coating film. This ensures that the non-magnetic SiO₂ layer can be closely controlled and minimized. The optimal SiO₂ content for complete (hermetic) encapsulation of the magnetic core particles was determined by isopropanol chemisorption.^[3] The magnetization of Fe₂O₃ coated with about 2 nm thin SiO₂ layers was nearly identical to that of uncoated, pure Fe₂O₃ nanoparticles.

[1] Teleki, A., M. Suter, P. R. Kidambi, O. Ergeneman, F. Krumeich, B. J. Nelson, and S. E. Pratsinis, Hermetically-coated superparamagnetic Fe₂O₃ particles with SiO₂ nanofilms, Chem. Mat. in press, (2009).

[2] Teleki, A., M. C. Heine, F. Krumeich, M. K. Akhtar, and S. E. Pratsinis, In situ coating of flame-made TiO₂ particles with nanothin SiO₂ films, Langmuir 24, 12553 (2008).

[3] Teleki, A., M. K. Akhtar, and S. E. Pratsinis, The quality of SiO₂ coatings on flame-made TiO₂-based nanoparticles, J. Mater. Chem. 18, 3547 (2008).

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See more of this Session: Magnetic Nanoparticles in Biotechnology and Biomedicine I
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