Facile synthesis of composite films featuring bulk superhydrophobicity, durability, and repairability for aquatic show

Synthesis of bulk superhydrophobic composite materials with durable and repairable properties is of important theoretical and practical significance. Herein, a bulk superhydrophobic composite film (BSCF) is fabricated by integrating organic polymer components, polyurethane acrylate (PUA) and polydimethylsiloxane (PDMS), and inorganic component, silica particles (SiO2). Due to the bulk deposition and construction of the covalently cross-linking polymer scaffolding, the composite film exhibits a unique bulk superhydrophobic property, which is capable of being exposed to the surface under mechanical shear to preserve durable superhydrophobicity. Therefore, the extreme water repellency of the BSCF maintains unaltered even cyclic sandpaper abrasion is conducted (>150 cycles). By exploiting the advantage of the extreme water repellency inside the composite film bulk, the BSCF is also able to repair its deprived superhydrophobicity via a sanding treatment (>30 cycles), which is completely different from the depletion of healing agents. Furthermore, the aquatic light-reflective function of superhydrophobic materials is exploited in this work for the first time and the exploitation of it may broaden the potential application fields of superhydrophobic materials in deep-sea exploitation, undersea transportation, and aquatic decoration. Based on the aquatic light-reflective principle, a series of patterns on the BSCF surface display dazzling light under the illumination of a flashlight and the aquatic show is successfully realized on each layer of the BSCF. Our studies convincingly show a new direction to synthesize composite materials featuring bulk superhydrophobic, durable, and repairable performances for various potential applications. [Display omitted] •A composite film based on polyurethane, polysiloxane, and silica is proposed.•The composite film exhibits a bulk superhydrophobic state.•The composite film possesses high damage-insensitive behavior.•The superhydrophobic film presents repairable ability via sanding treatment.•The aquatic show is successfully realized for the first time.