Covalently bonded polyaniline/graphene composites as high-performance electromagnetic (EM) wave absorption materials

In this work, the polyaniline nanorods/graphene sheets composites with covalent bond were synthesized through in-situ polymerization of aniline in the presence of amino-functionalized graphene sheets (AFG), in which polyaniline (PANI) polymerization is initiated by those amino groups on graphene. The chemical bonding between graphene and PANI is confirmed by several analytical techniques, including Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FESEM) and thermogravimetric analysis (TGA). The microwave-absorbing properties of the composites were measured by a vector network analyzer. The electromagnetic data demonstrates that the maximum reflection loss of covalently bonded PANI-AFG can reach −51.5 dB at 11.2 GHz, and the absorption bandwidths exceeding −10 dB are 4 GHz with thickness of 2.5 mm. The results indicate that the hybrid composites with enhanced microwave absorption properties and lightweight have a promising future in decreasing electromagnetic wave irradiation.