Flexible and multifunctional polyimide-based composite films by self-reducing reaction for electromagnetic interference shielding in extreme environments

With the continuous development of modern electronic technology, it is of great significance to explore materials with flexibility and stable electromagnetic interference shielding (EMI) properties in extreme environments. In response to this, a highly conductive polyimide-Ti3C2Tx MXene-silver nanoparticles (PI-MXene-AgNPs) com-posite film was prepared by performing a self-reduction reaction on the surface of poly(amic acid) nanofibers. The polyimide nanofibers are wrapped with Ti3C2Tx nanosheets and AgNPs. The film has excellent EMI shielding performance in X-band (8.2-12.4 GHz). When the mass ratio of MXene/AgNO3 is 4:1, the PI-MXene-AgNPs films have high absolute EMI shielding effectiveness up to 16785.67 dB cm2 g-1 at a thickness of 30 & mu; m. The com-posite film has stable EMI shielding performance even after high (300 degrees C) temperature, cryogenic (-196 degrees C), corrosive environment, multiple bending and physical shaking. Furthermore, PI-MXene-AgNPs films exhibit excellent flexibility and superior mechanical properties that can be maintained even after treatment under harsh conditions. In addition, the PI-MXene-AgNPs composite films show good versatility, such as photothermal conversion properties, antibacterial properties. Therefore, this work provides a feasible strategy for the prepa-ration of flexible electronic devices in extreme environments.