Flexible polymer-based films for electromagnetic interference (EMI) shielding show significant application importance. In this work, multilayer graphene oxide (MGO) was added to the aramid hydrogel dispersion after synthesizing nanofiber (ANF) hydrogel and MXene. Through a simple sequential vacuum-assisted filtration and freeze-drying method, (ANF/MGO)-MXene films with a Janus structure were prepared. The upper layer of this film consists of MXene, while the lower layer comprises ANF/MGO. This unique Janus architecture endows the (ANF/MGO)-MXene film with a distinctive “one-side conductive, and the other side insulating” characteristic. This structural design enables MXene to focus on delivering its electrical and electromagnetic functions while allowing the ANF/MGO layer to serve as a robust physical and safety safeguard. This allows the film to be directly and safely integrated into various electronic systems, wearable devices, or aerospace structures, functioning as an independent module that combines highly efficient electromagnetic shielding, active thermal management, outstanding mechanical strength, and inherent safety. This significantly broadens its application scenarios and reliability. Additionally, the film exhibits excellent mechanical properties, outstanding EMI shielding performance, as well as efficient electro-thermal and photo-thermal conversion capabilities. The MXene layer in the film exhibited a high conductivity of 82.42 S/cm and an EMI shielding effectiveness (SE) of 61 dB with the MXene content of 25 mg. The MXene layer rapidly responded to temperature changes under various applied voltages. When a voltage of 4 V was applied, the (ANF/MGO)-MXene film swiftly reached a stable temperature of 117℃. Under varying light power densities, both the ANF/MGO layer and MXene layer in the (ANF/MGO)-MXene film exhibited rapid temperature responses. Under simulated solar irradiation at 120 mW/cm 2 , the ANF/MGO layer maintained a stable surface temperature of 86℃, while the MXene layer stabilized at 50℃. The film also shows remarkable cycling stability and long-term durability in both electro-thermal and photo-thermal operations. Furthermore, the (ANF/MGO)-MXene film exhibits excellent flame retardancy, structural integrity, and mechanical strength. This work provides important insights into the design of MXene-based flexible films and suggests great potential for applications in wearable devices, sensors, and electronic communications.
Wang et al. (Fri,) studied this question.