Colloidal Route to Bio-inspired Hierarchical Superhydrophobic Substrates

Inspired by biomaterials such as the Lotus leaf and rose petals, we present a facile, inexpensive bottom-up colloidal route to prepare superhydrophobic surfaces with hierarchical roughness. Spin coating is used to assemble silica microspheres into multilayered arrays, which are subsequently decorated with gold nanoparticles. The surface chemistry of the silica and gold is modified by adsorption of fluoroalkylsilane and dodecanethiol, respectively. The wetting properties, both static and dynamic, of surfaces in relation to the morphology of the substrates are addressed.