Self-assembly alumina nanowires woven by Leidenfrost droplets

In this work, liquid oxalic acid was drawn into flaws of electro-polished aluminium foil during the immersion process by the capillary effect. When the foil was heated up, the volume expansion pushed liquid out of the flaws, forming Leidenfrost droplets on the foil because of surface tension. The spontaneous motion of the long-lasting Leidenfrost droplet influences one another and a trace of alumina is left behind on the reactive surface. Multi-scale self-assembly alumina nanowires were therefore formed on the surface of aluminium foil by the thermodynamics of the self-propelled Leidenfrost droplets. This novel surface nanostructuring method may have the potential for surface modification and coating.