(331f) Fabrication Of Non-Ageing Superhydrophobic Surfaces By Packing Flower-Like Hematite Particles

Superhydrophobic surfaces, characterized by a water contact angle of greater than 150º, have attracted considerable interest for applications in self-cleaning products and hydrodynamic drag reduction. However, ageing?deterioration of superhydrophobicity over time?is a major obstacle that hinders the practical application of artificial superhydrophobic surfaces. Here we demonstrate the fabrication of non-ageing superhydrophobic surfaces by packing flower-like micrometer-sized hematite (α-Fe2O3) particles. Although hematite is intrinsically hydrophilic, the nanometer-sized protrusions on the particles form textures with overhanging structures that prevent water from entering into the textures and induce a macroscopic superhydrophobic phenomenon. These superhydrophobic surfaces do not age even in extremely oxidative environments?they retain the superhydrophobicity after being stored in ambient laboratory air for 4 months, heated to 800ºC in air for 10 hours, and exposed to ultraviolet ozone for 10 hours. We anticipate that the demonstrated approach of packing flower-like particles could be applied to a variety of materials for fabrication of non-ageing superhydrophobic surfaces.