Dragonfly-Inspired Transparent Superhydrophobic Coatings with Low Haze and High Mechanical Robustness

Transparent superhydrophobic coatings hold significant potential for applications such as windows and reflectors. However, issues such as fragility and high haze have limited their practicality. Drawing inspiration from dragonfly structures, we developed a transparent superhydrophobic coating by etching the polystyrene microsphere array semiembedded on a silicon oxide matrix and subsequently depositing the methyltrichlorosilane-derived nanofilaments. The resulting coating features silicon oxide craters and nanofilaments inspired by dragonfly wings. Due to the coating's small, multiscale nanostructures, it has a high average visible light transmittance of 90.4% and a low average haze of 4.0%, comparable to the substrate glass. It also exhibits exceptional superhydrophobic properties, with a contact angle of 161.5° and a sliding angle of 1.5°. Notably, the coating retains its superhydrophobicity even after withstanding impacts from 5 kg of water and 500 g of sand, thanks to its robust wing vein-inspired protected structure. Additionally, it shows strong resistance to acids, alkalis, and temperatures up to 400 °C. The coating maintains a high transmittance and low haze after 67 days of UV irradiation or 300 days of outdoor exposure. The combination of low haze and robustness in this transparent superhydrophobic coating highlights its promising potential for applications in related fields.