Superhydrophobic photothermal MXene composite film for light-driven films

Abstract

Because of their safety, environmental friendliness, and simple operation, light-driven films are widely used in the fields of environment, biomedicine, and micromechanics. For light-driven films, moving the film on the liquid surface via the Marangoni effect is a convenient, mainstream approach. The efficient photothermal conversion can generate thermal Marangoni flow rapidly, and the superhydrophobicity can reduce the drag when the light-driven film moves on the liquid surface. In this work, a new strategy for preparing the composite film with excellent photothermal and superhydrophobic properties is proposed. The fSiO2/MG-WPU(fluoroalkylsilanes-SiO2/MXene@gold-waterborne polyurethane) film was obtained by simple spraying. The localized surface plasmon resonance effect improved the light absorption of MG(MXene@gold) hybrid, which is beneficial to the photothermal conversion. The absorption of the fSiO2/MA-WPU film reached 84% in the wavelength band from 300 to 1400 nm. The prepared MXene composite films show superhydrophobic property. The contact angle and sliding angle of the composite film reached to 154° and 2.3°, respectively. The film has good photothermal conversion ability, and its temperature reached 121 °C within 300 s (808 nm laser, 0.5 W/cm²). Combining high photothermal conversion and superhydrophobicity, the fSiO2/MG-WPU composite film achieved excellent performance for light driving. When irradiating with a laser power of 2 W/cm², the film linearly advanced 12.8 cm in 12 s. Furthermore, the film completed the actions such as clockwise rotation and counterclockwise rotation. The multifunctional fSiO2/MG-WPU composite film provides a new platform for remote control devices, light-driven micro-robots, reagent micro-transporters, etc.