Self-assembling, flexible and stable aramid nanofiber/polypyrrole/MXene composite film for efficient electromagnetic interference shielding, dual‑driven heating and infrared thermal camouflage

With the development of wearable devices, flexible multifunctional electromagnetic shielding (EMI) shielding materials have attracted widespread attention. In this paper, a fibrous ANF/PPy composite material was obtained by modifying aramid nanofibers (ANFs). Subsequently, the Ti 3 C 2 T x (MXene) suspension was mixed with the ANF/PPy solution, electrostatic self-assembly was performed, and an ANF/PPy/MXene composite film with a “brick (MXene)-mortar (ANF/PPy)” structure was prepared through vacuum-assisted filtration. The film has high electrical conductivity, certain mechanical tensile properties, high mechanical stability, good chemical stability, and excellent long-term stability. In addition, the film with a thickness of only 16 μm shows excellent EMI shielding (average EMI SE is 40.4 dB, absorption coefficient is 0.155, SSE/t is 36288.6 dB·cm 2 /g), dual‑driven (electrothermal and photothermal convertibility) heating and infrared thermal camouflage performance (radiation temperature is 69.4°C at a temperature of 150°C). These results show that ANF/PPy/MXene composite film is very promising in practical applications such as wearable devices, communications, high-performance heating, and infrared stealth.