Nano-grid enhanced hierarchical structure construction for a durable, bendable, anti-condensation and passive–active anti-/deicing surface

Abstract

Superhydrophobic surfaces exhibit exceptional suitability in various fields due to their moisture resistance. However, most artificial superhydrophobic surfaces are limited in low bendability and poor bonding strength, reducing long-term water repellence and hindering further application. In this study, a bendable superhydrophobic surface with a nano-grid enhanced hierarchical structure was developed to achieve strong bonding strength between superhydrophobic coatings and substrates. This coating was innovatively fabricated utilizing glass powders as the matrix and Al particles as photothermal fillers. Specifically, the nano-grid structure was prepared by anodic oxidation of Al particles to perform selective oxidation of the hierarchical structure as extra air-trapping sites, enabling superhydrophilicity and superhydrophobicity. The initial condensates on the superhydrophilic, hydrophobic and superhydrophobic surfaces were investigated theoretically and statistically using ESEM. It was found that the nano-grid structure helps single-droplet jumping without coalescence. Besides, the superhydrophobic surfaces presented excellent condensation resistance, as well as anti-icing and photothermal deicing effects. The coating can rapidly melt approximately a 3 mL ice column within 420 s under irradiation and expelled the melted water promptly, reducing the risk of secondary ice production. The surfaces displayed superhydrophobicity even when the samples were bent inward and outward into different curvatures and maintained superhydrophobicity after 25 cycles of sandpaper abrasion and 90 s of sandblasting. The superhydrophobic surfaces also exhibited good weathering resistance, paving way to practical outdoor applications.