Construction of strong and superhydrophobic MXene composite films by binary organosilane cross-linking for electromagnetic interference shielding and joule heating

Transition-metal carbide and/or nitride (MXene) with outstanding electrical conductivity and surface chemistry tunability shows great potential for constructing high-performance electromagnetic interference (EMI) shielding materials. Unfortunately, MXene has poor mechanical properties and ambient stability, limiting its practical applications. In this work, strong and superhydrophobic MXene/carboxymethylcellulose sodium (S-MC) composite films were prepared by blade coating followed by binary organosilane modification. Through the joint contributions of hydrogen-bonding interaction, alignment, and organosilane cross-linking of MXene nanosheets, the proposed S-MC films achieved outstanding mechanical properties and EMI shielding performance. For instance, the S-MC composite film containing 90 wt% MXene content demonstrated high specific EMI shielding effectiveness (152 069 dB/cm) and strong tensile strength (181.5 MPa), surpassing those of other reported MXene-based shields. The S-MC films also had excellent Joule heating performance with low applied voltage and quick thermal response. Furthermore, the binary organosilane cross-linking endowed the S-MC films with superhydrophobic properties by inducing rough surface and low surface energy, resulting in stable conductivity and EMI shielding performance in oxidizing and aqueous environments. The developed S-MC films showed enormous potential applications for EMI shielding and Joule heating. Our study offers a novel and scalable strategy to construct strong, stable, and multifunctional MXene-based composites.