Multifunctional flexible, crosslinked composites composed of trashed MXene sediment with high electromagnetic interference shielding performance

Developing novel nanomaterials for constructing multifunctional macrostructures in a facile, energy-efficient, sustainable, and scalable approach is urgently demanded yet remains highly challenging. Here, a type of freestanding, robust, highly flexible composite films composed of “trashed” MXene sediment (MS) are prepared in an ambient pressure casting approach. The typical green polymer of polyvinyl alcohol is employed to demonstrate the high potential of MS for constructing films with multifunctionalities, including electrically conductive, hydrophobic, photothermal, and electromagnetic interference (EMI) shielding performance. Upon the synergy of surface terminal functional groups, local defects, and numerous heterogeneous interfaces, the MS-based composites can have EMI shielding effectiveness (SE) of 76.2 dB in the X-band at the thickness of merely 590 µm and efficient SE value in the ultrabroadband frequency range of 8.2 to 40 GHz. Moreover, the EMI SE of the MS-based composites is widely controlled by adjusting the MS contents and film thickness. Combined with the sensitive and reliable photothermal performance, this work thus demonstrates a cost-effective, sustainable, and scalable strategy to prepare a type of multifunctional MS-based films with application potentials in thermal therapy, wearable electronics, electromagnetic compatible, and aerospace. Graphical Abstract The freestanding, yet robust and highly flexible composite films for EMI shields, which exhibits excellent mechanical strength and flexibility, good hydrophobicity, and water resistance.