Magnetic conducting composites based on polypyrrol and iron oxide nanoparticles synthesized via electrochemistry

In this work, the preparation of a polypyrrol-magnetite composite with good magnetic and electric properties is described. Firstly, the method consists of the electrochemical synthesis of magnetite nanoparticles 20 nm in diameter and narrow size distribution, and secondly, the encapsulation of the nanoparticles in a polymer matrix during its formation by chemical oxidation of the monomer. Particles appear well dispersed in the polymer matrix by transmission electron microscopy (TEM) while no degradation, in terms of nanoparticles size or magnetic properties during the polymer formation, seems to take place as it was revealed by X-ray diffraction and Mossbauer spectroscopy. Saturation magnetization increases with the amount of magnetic material present in the composite, but conductivity decreases in such a way that the amount of magnetic material was optimized to 10% with respect to the monomer to obtain a composite with high electrical conductivity and magnetic response. (C) 2009 Elsevier B.V. All rights reserved.