Title : Ultrafine silver nanowires-assisted physical and chemical cross-linking of MXene sheets with ultrahigh mechanical strength for exceptional electromagnetic interference shielding
Abstract:
The widespread adoption of wireless technology has transformed communication and information access, but it has introduced challenges such as electromagnetic interference (EMI) [2]. EMI disrupts electronic devices’ normal functioning and poses health risks. In environments saturated with EMI pollution, effective shielding materials are essential. MXenes (Ti3C2Tx) emerge as strong contenders for shielding due to their layered structure and excellent electrical conductivity. However, there are several challenges associated with these materials, including their weak interfacial interactions, which lead to inferior mechanical properties and structures of the MXene films, as well as a decline in conductivity and EMI shielding performance due to their poor oxidation stability. Efforts have been made to enhance the mechanical properties or oxidation stability of these films, but this often results in a trade-off with EMI shielding performance.
To address these issues, ultrafine Ag nanowires (AgNWs) have been used to achieve both physical and chemical cross-linking of MXene nanosheets and then embedded in PEDOT: PSS Polymer to enhance the mechanical strength. The weight percentage of AgNWs has been varied to tune the EMI shielding properties. The process involves drying these flexible and highly conductive composite films at ambient pressure, making it energy-efficient and scalable. Compared to traditional MXene films, the composites MXene films exhibit significantly improved mechanical strength, hydrophobicity, oxidation stability, and waterproofing capabilities, without sacrificing their excellent EMI shielding effectiveness (SE). Furthermore, these freestanding MXene based composite films can achieve a thickness of just 10 µm and maintain a SE of 65 dB. This results in ultrahigh surface-specific SE values of 25,500 dB cm2 g−1, respectively, surpassing those of previously reported MXene-based composite films. The induced porosity and meta structure effect, large flake sizes, presence of permanent or temporary dipoles in addition to higher electrical conductivity, helped to improve the EMI SE These results show that the films are light weight, less dense, mechanically strong and have high shielding effectiveness.
