Superparamagnetic Fe3O4 nanoparticles on graphene-polyaniline: Synthesis, characterization and their excellent electromagnetic absorption properties

The ternary nanocomposites of graphene-polyaniline-Fe3O4 (GN-PANI-Fe3O4) have been prepared via a two-step method, the chemical oxidative polymerization of aniline and subsequent in situ generation of superparamagnetic Fe3O4 nanoparticles by a co-precipitation method. The obtained ternary nanocomposites were characterized by XRD, FETEM, Raman spectroscopy, XPS, VSM and TG analysis. TEM studies reveal that Fe3O4 nanoparticles with the size in the range of 5-20 nm are uniformly dispersed on the surfaces of GN-PANI. The absorption mechanism of the ternary nanocomposites was also discussed. The investigation of the electromagnetic absorbability reveals that GN-PANI-Fe3O4 exhibits enhanced electromagnetic absorption properties compared to GN-PANI and GN-Fe3O4, which is mainly ascribed to the improved impedance matching, the geometric effect and the enhanced interfacial effects. The maximum reflection loss of the ternary nanocomposites is up to −43.9 dB at 11.4 GHz with absorber thickness of 2.5 mm. When the matching thicknesses vary from 2 to 4 mm, all the maximum reflection loss values are less than −24.2 dB. Our findings pave a different way to design excellent electromagnetic absorption materials.