Bioinspired, layered GNS/PNF nanocomposite film with electromagnetic interference shielding and fire-retardant properties

Lightweight, fire-resistant and electroconductive nanocomposite films with highly mechanical properties are being extensively researched to replace metals for the electromagnetic interference (EMI) shielding and electrothermal conversion. In this work, inspired by natural nacre, we successfully introduced poly(p-phenylene-2,6-benzobisoxazole) (PBO) nanofiber (PNF) into graphene nanosheets (GNSs) to prepare a series of GNS/PNF films with ordered layered structure and 3D nanofibers network. The GNS/PNF-60 film has a significant improvement of mechanical properties (tensile strength: 66.9 MPa, strain: 10.1 %) compared with pure graphene film. The GNS/PNF film reveals an EMI shielding effectiveness (SE) of 22.6 dB and a SSE/t value of 9521.4 dB cm2/g at 8.2 GHz, good Joule heating properties (temperature reaches 89.7 °C under 16 V applied voltage). Additionally, the GNS/PNF film with the low peak heat release rate (27.7 W g−1) presents the excellent flame retardancy. After superhydrophobic modification, the mechanical, EMI shielding, and electrothermal properties of the nanocomposite film can be well maintained.