Extreme environment-bearable polyimide film with a three-dimensional Ag microfiber conductive network for ultrahigh electromagnetic interference shielding

Abstract

To ensure the normal operation of electronic equipment and provide protection from electromagnetic radiation, polymer-based electromagnetic interference (EMI) shielding materials are widely developed in the electronic communication field. However, it remains a challenge to prepare EMI shielding composites with ultrahigh EMI shielding efficiency (EMI SE), low thickness, high durability, and flexibility in harsh environments, such as extremely high or low temperatures in aerospace. In this study, we used blow spinning and compression molding to construct a highly efficient EMI shielding polyimide (PI) film containing a Ag microfiber sponge (AgMS). The three-dimensional (3D) conductive network constructed by 28-vol% AgMS endows the AgMS/PI film with very high electrical conductivity of 4.5 × 106 S m−1 and an EMI SE of up to 90.6 dB, at only 20-µm thickness. Even after working at −196 or 250°C for 120 h, the excellent EMI shielding performance is maintained, with EMI SE retention higher than 85.1 dB. Furthermore, AgMS/PI film exhibits outstanding thermal management performance, achieving a high saturation temperature of 200.2°C at very low supplied voltage (1.1 V), revealing a quick response time (3.1 s), excellent cyclic heating stability, and outstanding reliability. These outstanding properties indicate the great potential of AgMS/PI films in the electronic communication field under harsh environments and artificial intelligence.