Fabrication and wetting behaviour of micro/nanostructured mushroom-shaped silver pillar surface

This manuscript presents a simple, one-step method for the fabrication of micro/nanostructured metal-based superhydrophobic surfaces via electroplating using stacked polycarbonate membranes with nanoscale and microscale pores as a template. The two-tiered mushroom-shaped silver pillar arrays include a top layer composed of nanopillars and a bottom layer composed of T-shaped micropillars. The presence of the re-entrant surface structures with a strong resistance pin the droplets to the cap's ridge and prevent water droplets from penetrating into the valleys of the rough surface, thus resulting in an increase in water contact angle (WCA). Compared with microstructured mushroom-shaped surfaces (WCA = 148 degrees, sliding angle (SA) similar to 26 degrees) and nanostructured surfaces (WCA = 151.5 degrees, SA similar to 4.8 degrees), the micro/nanostructured mushroom-shaped pillar arrays (WCA = 154.1 degrees, SA similar to 2 degrees) exhibit remarkable superhydrophobic properties with high CA and low SA. This new micro/nanostructured surface will have a potential application in metal-based superhydrophobic materials.