MXene-based multilayered flexible strain sensor integrating electromagnetic shielding and Joule heat

With the development of wearable intelligent devices, flexible textiles integrate high-performance sensing, electromagnetic shielding and Joule heating show broad application prospects. However, it is still difficult to improve all the performance simultaneously through simple methods. Here, we have prepared MXene/PU composite fiber film with multilayer porous network structure by using the electrospinning spraying alternate operation process. This film has ultra-high sensitivity (GF= 77,751), super large detection range (400%) and ultra-low detection limit (0.05%). Secondly, the multilayer fiber film has excellent EMI shielding performance (EMI SE=38 dB), and the EMI shielding capacity of the multilayer film can still exceed the commercial standard when it is stretched to 20%. Finally, the multilayer fiber film shows better Joule heating performance, including lower voltage drive (2 V) and faster thermal response (12 s). The excellent performance of the composite come from the synergistic effect of MXene and the unique multi-layer porous network structure. Among them, MXene provides excellent conductivity, electrothermal and electromagnetic shielding performance. The layered porous network structure can store the strain in advance and form a parallel circuit, which improves the sensing range, increases the transmission path of electromagnetic waves, and realizes the homogeneity of Joule heating. In addition, the outer PU slows down the invasion of oxygen, thus slows down the oxidation of MXene, and ensures the performance of materials in a long time. The multilayer fiber film has been proved to be suitable for sensing at low temperature, and has broad application prospects in wearability.