Hierarchical composites of polyaniline nanorod arrays covalently-grafted on the surfaces of graphene@Fe3O4@C with high microwave absorption performance

Two kinds of hierarchical structures of graphene@Fe3O4@C@PANI (polyaniline) nanorod arrays were prepared by covalently and noncovalently grafting PANI nanorod arrays to the surface of graphene@Fe3O4@C, respectively. The measured electromagnetic parameters show that the bonding form between PANI nanorod arrays and graphene@Fe3O4@C have significantly effect on microwave absorption properties of graphene@Fe3O4@C@PANI nanorod arrays hierarchical structures, and the formation of covalent bond between PANI nanorod arrays and graphene@Fe3O4@C in hierarchical structures exhibits significantly enhanced microwave absorption performance. The maximum reflection loss is up to -44.2 dB at 11.4 GHz and the absorption bandwidth with a reflection loss below -10 dB ranges from 9.7 to 15.5 GHz with a thickness of 3 mm. Therefore, the high microwave absorption performance with light-weight and wide absorption frequency band can be realized by fabricating graphene-based hierarchical structures using covalent bond interaction. (C) 2014 Elsevier Ltd. All rights reserved.