Dielectric and magnetic properties of conducting ferromagnetic composite of polyaniline with γ-Fe2O3 nanoparticles

The present paper reports the synthesis of conducting polyaniline polymer composite with nanoclusters of ferrite (gamma-Fe2O3) particles in the presence of dodecylbenzene sulfonic acid in aqueous medium through electrochemical and chemical oxidative polymerization. Different formulations have been prepared to study the effect of ferrite constituent on the electrical and dielectric properties of polyaniline nano-composite. Vibrating sample magnetometer (VSM) studies and electrical conductivity measurements have revealed that conducting polymer composite has a saturation magnetization (M-s) value of 48.9 emu g(-1) and conductivity of the order of 0.13 S cm(-1). The particle size of gamma-Fe2O3 was found in the range of 8-15 nm as analyzed by transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FTIR) results have shown the presence of characteristic band stretching of Fe-O band at 630 and 558 cm(-1), indicating the presence of gamma-Fe2O3 in the polyaniline matrix which is in agreement with the electrochemical results. Dielectric measurements have shown decreasing trend of dielectric constant with the increase of gamma-Fe2O3 particles in the polymer matrix while shielding effective (SE) of -11.2 dB was achieved for the polymer composite in 8.2-12.4 GHz (X-band) frequency range. The characterization of the composite was further carried out by X-ray diffraction, UV-vis and thermal gravimetric analysis (TGA). (C) 2008 Elsevier B.V. All rights reserved.