Highly Conductive PDMS Composite Mechanically Enhanced with 3D-Graphene Network for High-Performance EMI Shielding Application

A highly conductive three-dimensional (3D) graphene network (GN) was fabricated by chemical vapor deposition on a 3D nickel fiber network and subsequent etching process. Then a lightweight and flexible polydimethylsiloxane (PDMS)/GN composite was prepared by a vacuum infiltration method by using the graphene network as a template. The composite showed the superior electrical conductivity of 6100 S/m even at a very low loading level of graphene (1.2 wt %). As a result, an outstanding electromagnetic interference (EMI) shielding effectiveness (SE) of around 40 and 90 dB can be achieved in the X-band at thicknesses of 0.25 and 0.75 mm, respectively, which are much higher than most of the conductive polymers filled with carbon. The 3D graphene network can also act as a mechanical enhancer for PDMS. With a loading level of 1.2 wt %, the composite shows a significant increase by 256% in tensile strength.