Eur. Phys. J. D 49, 333-342 (2008)
https://doi.org/10.1140/epjd/e2008-00180-5

Nanocomposites of magnetic cobalt nanoparticles and cellulose

¹ Division of Materials Physics, Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland
² Hamburger Synchrotronstrahlungslabor HASYLAB at DESY, Notkestrasse 85, 22607 Hamburg, Germany
³ Division of Atmospheric Sciences and Geophysics, Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland
⁴ Laboratory of Optics and Molecular Materials, Helsinki University of Technology, P.O. Box 5100, 02015 TKK, Finland
⁵ Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 St. Petersburg, Russia

Corresponding author: ^a kari.pirkkalainen@helsinki.fi

Received: 6 May 2008
Revised: 6 August 2008
Published online: 3 October 2008

Abstract

Polymeric matrices with stabilized metallic nanoparticles constitute an important class of nanostructured materials, because polymer technology allows fabrication of components with various electronic, magnetic and mechanical properties. The porous cellulose matrix has been shown to be a useful support material for platinum, palladium, silver, copper and nickel nanoparticles. In the present study, nanosized cobalt particles with enhanced magnetic properties were made by chemical reduction within a microcrystalline cellulose (MCC) matrix. Two different chemical reducers, NaBH₄ and NaH₂PO₂, were used, and the so-formed nanoparticles were characterized with X-ray absorption spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. These experimental techniques were used to gain insight into the effect of different synthesis routes on structural properties of the nanoparticles. Magnetic properties of the nanoparticles were studied using a vibrating sample magnetometer. Particles made via the NaBH₄ reduction were amorphous Co–B or Co oxide composites with diminished ferromagnetic behaviour and particles made via the NaH₂PO₂ reduction were well-ordered ferromagnetic hcp cobalt nanocrystals.