PVDF/MWCNTs/RGO@Fe3O4/AgNWs composite film with a bilayer structure for high EMI shielding and electrical conductivity

Abstract With the renewal of electromagnetic shielding materials, conducting polymer electromagnetic shielding composites stand out. In the article, ferric tetraoxide‐modified reduced graphene oxide (RGO@Fe 3 O 4 ), silver nanowires (AgNWs) and polyvinylpyrrolidone (PVP K30) were blended to form a solution colloid, and polyvinylidene fluoride/carbon nanotubes (PVDF/MWCNTs)‐3 wt% composite film was used as the substrate, then the PVDF‐based bilayer composite films were prepared by vacuum‐assisted filtration (VNF).When RGO@Fe 3 O 4 was added in the amount of 10 mL, the electrical conductivity of PVDF/MWCNTs/RGO@Fe 3 O 4 ‐10 bilayer composite film is 1.7 × 10 1 S·m −1 , the total electromagnetic shielding effectiveness (EMI SE T ) was 20.4 dB, of which the absorption loss accounted for 82.4%, and the specific electromagnetic shielding effectiveness (SSE/t) was 590.9 dB/(cm 2 ·g −1 ). After the addition of 25 mL AgNWs, the electrical conductivity of PVDF/MWCNTs/RGO@Fe 3 O 4 /AgNWs‐25 bilayer composite film up to 4.9 × 10 4 S·m −1 , the EMI SE T was 94.4 dB, of which the absorption loss accounted for 85.4%, and the specific electromagnetic shielding effectiveness (SSE/t) was 3629.3 dB/(cm 2 ·g −1 ). It indicates that the electromagnetic shielding mechanism of both bilayer composite films is dominated by absorption loss. The addition of RGO@Fe 3 O 4 /AgNWs increases the electrical conductivity and electromagnetic shielding effectiveness of the bilayer composite films more than RGO@Fe 3 O 4 . The successful preparation of this bilayer composite film makes it possible to form lightweight superconducting nanoparticles from high‐density metal‐modified carbon‐based materials, which provides an easy method for the preparation of highly conductive electromagnetic shielding composites. Highlights In this article, well dispersed highly conductive‐doped nanomaterials Fe3O4@RGO were prepared and characterized by hydrothermal synthesis. In this article, silver nanowires with good conductivity and high aspect ratio were prepared and characterized by liquid phase polyol method. In this article, three‐dimensional mesh PVDF‐based bilayer composite films with more excellent electromagnetic shielding properties were prepared by solution blending and vacuum‐assisted filtration using PVDF/MWCNTs‐3 wt% composite films as substrates. In this article, the electromagnetic shielding mechanism of bilayer composite films is discussed from the knowledge of three‐dimensional aspects.