3D network porous polymeric composites with outstanding electromagnetic interference shielding

A novel and highly efficient technique, combination of hot-pressing and selective etching, was proposed to manufacture porous nanocomposites based on poly(vinylidene fluoride) (PVDF) and multiwall carbon nanotubes (MWCNTs) with three-dimensional(3D) networks. Benefitting from the 3D conductive network, a dramatic change in electrical conductivity was observed from 10−16 S cm−1 for pure PVDF to 1 S cm−1 for porous nanocomposites (at 15 wt% MWCNTs loading). In addition, the obtained porous composites achieved an electromagnetic interference (EMI) shielding effectiveness (SE) of approximately 56.72 dB with a density of 0.79 g cm−3 and a thickness of only 2 mm. The EMI shielding mechanisms of such porous materials were also discussed and it suggested that the dominant contribution to EMI SE was absorption rather than reflection in the X-band frequency region.