Bioinspired Mechanically Robust Metal-based Water Repellent Surface enabled by Scalably Constructing a Flexible Coral-Reef Like Cu based Architecture

Good mechanical robustness has been a central concern for moving artificial superhydrophobic surfaces with extremely aqueous repellency to application practices. Avoiding use of micro/nano architecture composed bulk hydrophilic material becomes a common sense to prevent exposure of hydrophilic surface and thereby non-wettability degradation. Meanwhile, inexpensive scalable and mechanically durable, adherent, scalable, and techniques are still in demand. To address these challenges, here we demonstrated robust mechanical durability of superhydrophobic surface with metal (hydrophilic) textures through scalable construction of a flexible coral-reef like Cu hierarchical architecture on varies of substrate including metals, glasses and ceramics. Discontinuous micro-scale coral-reef like Cu architecture is built by kinetic spraying commercial electrolytic Cu particles (15-45 ?m). Subsequent flame oxidation is applied to introduced a porous surface oxide layer and increase the roughness. The fluorinated surface remains its water repellency with extremely low roll-off angle (1o) after cyclic bending/folding, sand-grit erosion, knife-scratch and even heavy loading of acid rain droplets hitting. Strong adhesion to glass, ceramics and metals up to 34 MPa can be achieved without applying any adhesive. The results indicate that the flexible Cu based superhydrophobic coating could have including out-door self-cleaning, lag-reduction, anti-biofoiling and especially corrosion protection of metal parts in aqueous environment.