Electrical percolation networks of MWCNT/Graphene/Polyaniline nanocomposites with enhanced electromagnetic interference shielding efficiency

Polymer-based electromagnetic interference (EMI) shielding effectiveness (SE) composite materials play a crucial role in electronics, telecommunications, healthcare, and military fields. However, the electrical percolation networks and the interface structures between polymer chains and conductive fillers still cannot be directly obtained by experimental observation, which plays a decisive role in EMI SE. In this work, multi-walled carbon nanotubes (MWCNT) / graphene (Gr) / polyaniline (PANI) films with electrical percolation network structures were prepared by electrochemical deposition, and the forming process of percolated networks and the interface structures can be directly observed by all atom molecular dynamics simulations. Compared with the MWCNT/Gr film, the EMI shielding effectiveness (SE) of the ternary film deposited with PANI rises by 35.6 %, and the conductivity increases by 126 %. The EMI SE of the film reaches 78 dB at 10 GHz when the thickness is about 292 μm. The improvement of EMI SE is attributed from the reduction of flaws and voids of film, the formation of electrical percolation network as well as an increase in lamellar spacing of Gr nanosheets with PANI deposition.