Sandwich structures of graphene@Fe3O4@PANI decorated with TiO2 nanosheets for enhanced electromagnetic wave absorption properties

The novel sandwich structures of graphene@Fe3O4@PANI decorated with TiO2 nanosheets were firstly successfully prepared by simple hydrothermal method and in situ polymerization. VSM results reveal that the nanocomposites have a superparamagnetic behavior. Structure and morphology were characterized by X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. Electron microscopy images show that TiO2 nanosheets are mostly grown upright on the top of graphene@Fe3O4@PANI support with a random orientation, and form hierarchical structures. Electromagnetic (EM) wave absorption properties of graphene@Fe3O4@PANI@TiO2 nanosheets containing 50wt% paraffin were investigated in the frequency region of 2-18 GHz. The maximum reflection loss of the nanocomposites is up to -41.8 dB at 14.4 GHz with a thickness of 1.6 mm, and the absorption bandwidth of R-L < - 10 dB is almost up to 3.5 GHz. Thus, the enhanced EM wave absorption properties of graphene@Fe3O4@PANI@TiO2 nanosheets can be used as promising EM wave absorbers. (C) 2015 Elsevier B.V. All rights reserved.