Nanostructured aramid fiber/Cu/BN composite Janus films with broadband electromagnetic interference shielding and superior thermally conductive/electrically insulating performance

Modern electronic technology necessitates the development of composite materials with effective electromagnetic protection. This work presents a novel strategy constructing an aramid nanofiber (ANF)-based Janus film (ANF@Cu-ANF/BN) using an electroless plating-vacuum assisted filtration-pressing technique. The film exhibits an unique asymmetric property profile, with one side being electrically conductive and thermally conductive/electrically insulating on the other. Exceptional EMI shielding effectiveness of 105.22 and 106.96 dB is obtained in the 8.2–12.4 GHz and 26.5–40 GHz ranges, respectively. In addition, the film demonstrates an impressive out-of-plane thermal conductivity of 2.703 W/(m·K). suggesting superior thermal management capabilities when integrated into heat sinks for high-power light-emitting diode modules. In terms of mechanical robustness, the film possesses a tensile strength of 14.31 MPa. The ANF@Cu-ANF/BN Janus composite films effectively harmonize electromagnetic shielding , thermal conductivity , and mechanical integrity, offering an innovative pathway of developing advanced materials that fulfill the stringent requirements of modern electronic devices. • Aramid nanofibres coated with copper nanoparticles were achieved. • The Janus films exhibited electrically conductive (1593.65 S/cm)/insulating (5.55 × 10 9 Ω·cm) asymmetric property. • The Janus films showed superior EMI SE, reaching values of 105.22 and 106.96 dB within the X and Ka bands, respectively. • The Janus composites demonstrated an impressive out-of-plane thermal conductivity of 2.703 W/(m·K).