Mechanically strong and environmentally stable MXene films reinforced by CNT-embedded aramid nanofibers for electromagnetic interference shielding

Developing novel transition metal carbides/nitrides (MXene)-based electromagnetic interference (EMI) shielding composites with excellent mechanical properties and oxidation resistance is urgently demanded but remains hugely challenging thanks to the increasingly sophisticated application scenarios. Herein, we demonstrated an interfacial engineering and sequential assembling strategy to synergistically address the above problems. Carbon nanotubes (CNT) were utilized to assist the splitting preparation of aramid nanofibers (ANF) and chemical cross-linking to construct a substrate layer that served to provide mechanical properties. Polydopamine (PDA) was modified onto MXene surface (PMXene) by in situ polymerization and binding, generating an adhesive layer to prevent oxygen penetration effectively. The resultant Janus-structured PMXene-CNT/ANF films exhibited outstanding mechanical performances including high tensile strength (366.8 MPa) and toughness (69.3 MJ m −3 ), superb electrical conductivity (3548.8 S cm −1 ), impressive EMI shielding effectiveness (EMI SE 55.5 dB) and EMI SE/t (14128.2 dB cm −1 ), as well as excellent oxidation stability. Furthermore, the flexible films displayed distinguished Joule-heating performances and fast and sensitive temperature response at external voltage. Therefore, such composite films with excellent mechanical properties and environmental stability have great practical value in flexible electronics and military electronic equipment for EMI shielding, and the polar-exploration equipment for anti-icing and de-icing.