Enhanced microwave absorption performances of polyaniline/graphene aerogel by covalent bonding

In this paper, covalently bonded polyaniline (PANI)/graphene aerogel (GA) was synthesized using hydrothermal and in-situ polymerization techniques. The chemical bonding between PANI and GA and the micro-morphological features of the aerogel were investigated employing several characterization methods, which included Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Due to combination of appropriate impedance match, synergistic effects, and hierarchical nanostructures of PANI and GA, the hybrids exhibited obviously improved microwave absorption performances, compared to GA. The PANI/GA showed the strongest reflection loss (R-L) of -42.3 dB at 11.2 GHz with a matching thickness of 3 mm, and the corresponding absorption bandwidth (R-L < -10 dB) was almost 3.2 GHz (8.7-11.9 GHz). Taking into account the superior microwave absorption properties of PANI/GA, the strategy of covalently bonding PANI nanorods on GA is an effective way for obtaining a high-performance microwave absorber.