Facile synthesis, magnetic and microwave absorption properties of Fe3O4/polypyrrole core/shell nanocomposite

Fe3O4/polypyrrole (PPy) core/shell nanocomposite, with Fe3O4 nanoparticle as core and PPy as shell, could be facilely synthesized via in situ chemical oxidative polymerization of pyrrole monomers on the surface of Fe3O4 nanoparticles. The results indicate that core/shell nanocomposite consists of Fe3O4 core with the mean diameter of 100 nm and adjacent PPy shell with a thickness of about 70 nm. The as-prepared Fe3O4/PPy core/shell nanocomposite exhibits a saturated magnetization of 20.1 emu/g and coercivity value of 368.3 Oe, respectively. The electromagnetic characteristics of Fe3O4/PPy core/shell nanocomposite were also investigated with a vector network analyzer in the 2-18 GHz range. The absorbing peak position moves to lower frequency with increasing the thicknesses of samples. The value of the minimum reflection loss is -22.4 dB at 12.9 GHz for Fe3O4/PPy core/shell nanocomposite with a thickness of 2.3 mm, and a broad peak with a bandwidth lower than -10 dB is about 5 GHz. Such strong absorption is attributed to better electromagnetic matching due to the existence of PPy and the special core/shell structure. (C) 2010 Elsevier B.V. All rights reserved.