Rare earth ions doped polyaniline/cobalt ferrite nanocomposites via a novel coordination-oxidative polymerization-hydrothermal route: Preparation and microwave-absorbing properties

Polyaniline/CoRExFe2−xO4 (RE=La, Ce, Y, x=0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70nm and a length longer than 2μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca. 10–20nm. Microwave absorption properties of polyaniline/CoRExFe2−xO4 nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLaxFe2−xO4 nanocomposite, the optimal microwave absorption performance is at x=0.15, that is, the mass ratio of La in CoLaxFe2−xO4 is 7.5%, with the conductivity of the composite about 0.833S/cm. Furthermore, when the layer thickness is 2mm, the maximum reflection loss achieves the maximum number of −42.65dB at 15.91GHz with a bandwidth of 6.14GHz above −10dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity.