Artificial lotus leaf structures made by blasting with sodium bicarbonate

Superhydrophobic surfaces have superior hydrophobicity and micro-nano hierarchical structures like those on the lotus leaf. The conventional methods used for the fabrication of microstructures involve delicate and time-consuming processes. We report here a simple and cost-effective method for fabricating artificial lotus-leaf-like structures with uniform superhydrophobicity; this method is based on a blasting process with sodium bicarbonate. Sodium bicarbonate, a water-soluble material, can be easily cleaned off an Al surface by the addition of oxalic acid to the anodizing solution. Therefore, microparticles do not need to be removed in a separate process. The resulting hierarchical structures are suitable for diverse applications, including microfluidic devices for biological studies and industrial self-cleaning products for automobiles, ships and houses.