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

With the renewal of electromagnetic shielding materials, conducting polymer electromagnetic shielding composites stand out. In the article, ferric tetraoxide-modified reduced graphene oxide (RGO@Fe3O4), 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@Fe3O4 was added in the amount of 10 mL, the electrical conductivity of PVDF/MWCNTs/RGO@Fe3O4-10 bilayer composite film is 1.7 x 10(1) S<middle dot>m(-1), the total electromagnetic shielding effectiveness (EMI SET) 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)<middle dot>g(-1)). After the addition of 25 mL AgNWs, the electrical conductivity of PVDF/MWCNTs/RGO@Fe3O4/AgNWs-25 bilayer composite film up to 4.9 x 10(4) S<middle dot>m(-1), the EMI SET 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)<middle dot>g(-1)). It indicates that the electromagnetic shielding mechanism of both bilayer composite films is dominated by absorption loss. The addition of RGO@Fe3O4/AgNWs increases the electrical conductivity and electromagnetic shielding effectiveness of the bilayer composite films more than RGO@Fe3O4. 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.