Highly Flexible and Ultralight PVA-co-PE-AgNW/MXene Composite Film with Low Filling for Multistage Electromagnetic Interference Shielding.

A composite film with multistage mechanisms for effective electromagnetic interference (EMI) shielding in the ultra-wide frequency of 8-20 GHz was designed. Poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibers and twill-structured nylon 6 fabric are used as substrate and filter film, respectively. Subsequently, a PVA-co-PE/silver nanowire (AgNW)/MXene (PVA/Ag/M) composite film is prepared by vacuum filtration, templating, and hot-pressing. A 2.5 wt.% AgNW/MXene content, the EMI shielding efficiency (SE), normalized SE (SE/t), and absolute SE (SSE/t) are 101.6 dB, 7008.3 dB cm, and 36501.5 dB cm g, respectively. These results are attributed to the synergistic EMI shielding mechanisms enabled by the twill gradient structure and highly conductive. The surface twill structure promotes 95% wave adsorption, directing the wave along the film interior, significantly increasing the EM wave collision probability and internal reflection times. The rich number of hydrogen bonds increase the interfacial adhesion between the layers and enhance the tensile stress by up to 26.8 MPa. The PVA/Ag/M exhibits excellent Joule heating, rapid heat dissipation, non-flammability, hydrophobicity, super-flexibility, and stability. This paper presents an effective fabrication strategy for ultralight and highly conformable low-filling films with high strength, excellent EMI SE, and outstanding thermal performance.