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 outof-plane thermal conductivity of 2.703 W/(m & sdot;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.