Monday, November 5, 2007 - 10:00 AM
44d

Processing and Structure of Magnetic C/co-Polymer Nanocomposites with up to 90 Wt% Metal Content

Norman A. Luechinger1, Loher Stefan1, Robert N. Grass1, Evagelos K. Athanassiou1, Sri Bandyopadhyay2, Greg Heness3, Norman Booth4, and Wendelin J. Stark1. (1) Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH Zurich), Wolfgang-Pauli-Str. 10, ETH Hönggerberg, Zurich, 8093, Switzerland, (2) School of Materials Science and Engineering, University of New South Wales, NSW, 2052, Australia, (3) Department of Physics and Advanced Materials, University of Technology, NSW, 2007, Australia, (4) Department of Chemistry, Materials and Forensic Science, University of Technology, NSW, 2007, Australia

Magnetic and electrically conducting polymer composites offer significant advantages over their metallic or ceramic counterparts concerning light-weight construction, corrosion resistance or the potential to obtain complex-shaped parts at high production rates using conventional polymer processing. Potential applications of these materials could be found in electrical engines, magnetic actuators or electronic devices with tunable electrical resistivity.

This contribution reports on the preparation of electrically conducting soft magnetic polymer composites by incorporating carbon-coated cobalt nanoparticles of different loadings into two types of polymers using a solution based method or dry mixing. Both preparation methods revealed completely different morphological structures of the composites as well as corresponding electrical properties. The electrical resistivity of the nanocomposites could be tuned over a range of about 10 orders of magnitude.

Figure: Air-stable cobalt nanoparticles have been prepared by reducing flame spray synthesis (left). Electron micrographs revealed an about 1nm thick oligo-graphene carbolayer protecting the metallic core. Composites with up to 90 wt% Co were fully melt processable (right).

References:

Grass, R. N. and Athanassiou, E. K., W. J. Stark, Covalently functionalized cobalt nanoparticles as a platform for inexpensive magnetic separations in organic synthesis, Angewandte Chemie, accepted (2007).

Athanassiou, E. K., R. N. Grass, et al. (2006). Large-scale production of carbon-coated copper nanoparticles for sensor applications. Nanotechnology 17(6): 1668-1673.

Grass, R. N. and W. J. Stark (2006). Gas phase synthesis of fcc-cobalt nanoparticles. Journal of Materials Chemistry 16(19): 1825-1830.

Luechinger, N. A., S. Loher, et al. (2007). Highly sensitive optical detection of humidity on polymer/metal nanoparticle hybrid films. Langmuir 23(6): 3473-3477.

R. Grass, E. Athanassiou, W. J. Stark, Flame synthesis of metal nanoparticles, applied as PCT (internationally), 2005.


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