Thermoconductive Ultralong Copper Nanowire-Based Aramid Nanofiber Nanopapers for Electromagnetic Interference Shielding

Nowadays, the advancement of thermoconductive electromagnetic interference (EMI) shielding materials for the next generation of electronics is in high demand. We present, in this research, the fabrication of the highly thermoconductive nanopapers based on aramid nanofiber (ANF) and ultralong copper nanowires (ULCuNWs) with outstanding EMI shielding effectiveness (SE) and mechanical properties. A homogeneous red brick color nanopaper (thickness 40–50 μm) was fabricated by homogenizing a mixture of the ULCuNWs (10–40 wt %) in the ANF suspension, then vacuum filtration, and drying. The morphology of the nanopapers reveals that the ULCuNWs were uniformly dispersed and interweaved with ANF to form two-dimensional (2D) layers in the nanopapers. With the increase in the ULCuNWs content, the nanopaper shows outstanding mechanical properties and reaches the optimal tensile strength (σ) of 228 MPa and Young's modulus of 6.12 GPa at the filler content of 30 wt %. Moreover, the variation of the in-plane thermal conductivity (λ//) and EMI SE of the nanopapers strongly depends on the amount of the ULCuNWs; the ULCuNWs30/ANF nanopapers obtain a notable λ// and EMI SE of around 8.25 W·m–1·K1 and 54.7 dB, respectively, with the mass content of 30 wt % at ambient conditions. The thermal treatment of the ULCuNWs30/ANF nanopapers at 180 °C increases the λ// and EMI SE by 60% and 9%, respectively. The ULCuNWs30/ANF nanopaper demonstrates an impressive heat dissipating capability. In addition, the ULCuNWs/ANF nanopapers show eminent thermal stability up to 500 °C and flame retardancy with an extremely low total heat release of 0.72 kJ·g–1. Therefore, ULCuNWs/ANF nanopapers can be considered great potential materials alternative to the current thermoconductive materials for heat dissipating applications in modern electronics.