Multifunctional sandwich-like composite film based on superhydrophobic MXene for self-cleaning, photodynamic and antimicrobial applications

• Surface functionalization endow MXene with superhydrophobicity and stability. • Superhydrophobic MXene-based composite film (FMX-T) with nanocellulose was prepared. • Sandwich-like structure of FMX-T film solves brittleness of MXene-based film. • FMX-T film shows self-cleaning and high photothermal conversion capacity. • FMX-T film achieves light-driven motion and long-lasting antibacterial properties. Although Ti 3 C 2 T x MXene has been widely investigated for diverse applications due to its excellent performance, it has long faced challenges such as hydrophilicity, oxidation susceptibility and poor mechanical properties. In this work, surface functionalization using perfluorosilane (PFOTS) was applied to endow MXene with super-hydrophobicity, improving its stability, and the resulting materials remained unaltered after at least 150 days. Superhydrophobic composite film with a sandwich-like structure was prepared from superhydrophobic MXene and TEMPO-oxidized nanocellulose through layer-by-layer self-assembly method. The resulting hybrid film exhibits exceptional flexibility and strength, which could be fold into various shapes and easily support a considerable weight ( ca. 1 kg). The superhydrophobic composite film displays a high-water contact angle of over 153°, showing excellent self-cleaning ability, water repellency and durability. The composite film also shows high photothermal conversion capacity and stability, being able to rapidly increase the temperature over 100 °C under NIR laser irradiation, maintaining it during long time. Interestingly, the combination of super-hydrophobicity and photothermal conversion ability of the composite film successfully achieves controllable light-driven motion and enhanced antibacterial properties by the simultaneous integration of super-hydrophobicity, antiadhesion and long-lasting photothermal sterilization properties. The resulting multifunctional film not only expands knowledge of superhydrophobic surfaces, but also provides valuable new options and strategies for potential applications in light-sensitive robotics, free-standing flexible electronic solids, and improved antibacterial materials.