Applied Voltage and Near-Infrared Light Enable Healing of Superhydrophobicity Loss Caused by Severe Scratches in Conductive Superhydrophobic Films

The fabrication of self-healing/healable superhydrophobic films that can conveniently and repeatedly restore the loss of superhydrophobicity caused by severe mechanical damage, such as deep and wide surface scratches, remains challenging. In the present work, conductive superhydrophobic films that are healable by means of an applied voltage or near infrared (NIR) light irradiation are fabricated by depositing a layer of Ag nanoparticles and Ag nanowires (AgNPs-AgNWs) on a thermally healable polycaprolactone (PCL)/poly(vinyl alcohol) (PVA) composite film, followed by the deposition of 1H, 1H, 2H, 2H-perfluorodecanethiol. The AgNPs-AgNWs layer not only provides micro-and nanoscaled hierarchical structures in support of superhydrophobicity but also serves as an electrothermal or photothermal heater to enable healing of the underlying PCL/PVA film under the assistance of a low applied voltage or low-power NIR light irradiation. Because of the strong adhesion between the PCL/PVA film and the AgNPs-AgNWs layer, the healability of the PCL/PVA film is successfully conveyed to the conductive superhydrophobic layer, which can rapidly and repeatedly restore the loss of superhydrophobicity caused by cuts several hundreds of micrometers wide. The combined electrothermal and superhydrophobic properties endow the healable conductive superhydrophobic films with improved durability and usefulness as self-cleaning, antiicing, and snow-removing surfaces.