Well-designed structure of sandwich-like composite films based on hollow polyaniline and MXene with enhanced electromagnetic wave absorption

With science and technology developing rapidly nowadays, intellective, carriable, and wearable electronic devices have also developed quickly. So far, the demand for composite films with remarkable electromagnetic interference (EMI) shielding performance is increasingly urgent. In this paper, a sandwich-like EMI shielding composite film was prepared by alternating vacuum-assisted filtration method, where hollow polyaniline (h-PANI)/cellulose nanofiber (CNF) in the surface layers and MXene/CNF in the intermediate layer. Due to the successful construction of the sandwich structure, when the proportion of MXene is just 8 wt% and h-PANI is 24 wt%, the EMI SE of the sandwich-structured composite films achieved 35.3 dB, which is better than that of the homogeneously blended film (17.3 dB) and the improvement of the SET is mainly caused by the increase of SEA. Besides, the EMI SE of the composite film did not reduce observably even after ultrasonic, stripping, bending and other treatments, indicating that it has good EMI shielding stability. More interestingly, the absorption coefficient of the sandwich-structured composite films with h-PANI was improved by 325% contradistinguish to that of the pure CNF layer structure. This novel sandwich composite film exhibits excellent EMI shielding performance with broad application prospects in intelligent, portable, and wearable fields.