Creating superhydrophobic surfaces with flowery structures on nickel substrates through a wet-chemical-process

Stable and durable superhydrophobic surfaces have been fabricated on nickel substrates with a convenient wet-chemical-process by using monoalkyl phosphonic acid. Scanning electron microscopy (SEM) observation revealed that flowery microstructures gradually formed and constituted a continuous slipcover over the nickel surfaces, while the nickel surfaces transformed from hydrophilic to superhydrophobic during the steeping process. The petals of the nanoflowers consisted of lamellar crystals resulting from the self-assembly of alkyl phosphonates. The surface roughness as well as the wettability can be tailored synchronously by controlling the steeping time and using phosphonic acids with different alkyl groups. This approach is easily developed to other engineering metal substrates such as steel.