Flexible aramid nanofiber/Ag nanowires/graphene nanosheets composite films with sandwich structure for high-performance electromagnetic interference shielding and Joule heating

Multifunctional materials have attracted tremendous attention owing to their applications in military, healthcare and medical therapy, intelligent and wearable devices. Herein, multifunctional sandwich structure composite film consisting with aramid nanofiber (ANF), silver nanowires (AgNWs) and graphene nanosheets (GNs) is fabricated via a facile vacuum filtration following a hot-pressing method, which is applied in electromagnetic interference (EMI) shielding and Joule heating. ANF/AgNWs/GNs (AAG) sandwich structure composite film not only realizes excellent EMI shielding performance but also possesses outstanding Joule heating property due to with high electrical conductivity owing to AgNWs network layer. EMI shielding and Joule heating performance of AAG composite films are gradually enhanced with increasing the mass ratio of AgNWs, which can be attributed to the increase of electrical conductivity. When the mass of AgNWs is increased to 30 mg, AAG-24 g m−2 composite film with thickness of 40 µm displays a superior EMI shielding effectiveness of 68.3 dB and specific shielding effectiveness of 16,545.4 dB cm−2 g−1. In addition, the surface temperature of AAG-24 g m−2 film reaches approximately 133 °C at a low working voltage of 3.0 V. This work introduces that the multifunctional sandwich structure composite films with an excellent EMI shielding and Joule heating performance have a huge potential application for numerous actual fields.