Ultrathin Flexible ANF/AgNWs/MWCNTs-PEDOT:PSS Composite Films for Electric Heating and Electromagnetic Interference Shielding

With the development of 5G communication technology, electronic devices face the challenge of performance fluctuations when exposed to temperature-varying environments and multiband electromagnetic radiation. Addressing the limited performance of single-component materials, this article proposes a design strategy for synergistically enhanced composite films. Through the synergistic effects of multiple components and the regulation of multidimensional structures, the performance limitations of functional materials are overcome. In this work, a hierarchical aramid nanofiber (ANF)/silver nanowire (AgNWs)/multiwalled carbon nanotube (MWCNTs)-poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composite film was fabricated via stepwise vacuum filtration. The bottom-layer ANF provides robust mechanical stability, and AgNWs in the interlayer form the primary conductive network. The top-layer MWCNTs-PEDOT:PSS with a “reinforced-concrete” structure significantly enhances the interfacial adhesion between AgNWs and ANF layers. This architecture fills conductive network gaps, creates additional pathways, and retards AgNWs’ oxidation effectively. The composite film retains excellent mechanical properties with a tensile strength of 231.67 MPa. It exhibits a rapid electrothermal response, reaching 122 °C from room temperature within 15 s under a low voltage of 4 V. Meanwhile, its electromagnetic interference (EMI) shielding effectiveness in the X-band reaches 35.57 dB. It overcomes the performance limitations caused by uneven dispersion of traditional fillers and poor interfacial adhesion. These advantages endow it with great potential in various fields, such as smart wearable devices, aerospace engineering, flexible electronics, and medical applications.