Ferromagnetic carbonized polyaniline/nanodiamond hybrids for ultrabroad-band electromagnetic absorption

Carbonized polyaniline/nanodiamond hybrids were synthesized using an in situ polymerization and carbonization method, in which polyaniline aided to stabilize nanodiamond and prevent it from re-aggregation. Polyaniline also acted as nitrogen source, constructing nanodiamond interface/surface C⋯N hybridization during the carbonization. Q = N and C⋯N = Q groups, which could enhance the dielectric polarization, were proved to exist in the carbonized hybrids. On the other hand, doping nitrogen into nanodiamond resulted in ferromagnetism, which could couple the dielectric and magnetic dissipation. The carbonized hybrids exhibited remarkable ultrabroad-band electromagnetic absorption. The optimal reflection loss peak could reach −46.0 dB at 12.2 GHz and the bandwidth below −10 dB was 12 GHz covering 6–18 GHz. The broadband and high electromagnetic absorption were mainly attributed to the Q = N and C⋯N = Q groups’ dual polarization enhancement, nitrogen-doping induced magnetic effects, as well as the collaborative nitrogen-doped interface network. This work provides novel referencing path for the design of broadband electromagnetic absorption materials, especially for heteroatom doped carbon nanomaterials.