A facile method to fabricate hierarchical particulates for superhydrophobic surfaces by diisocyanate reactions

In this article, cauliflower-like particulates with hierarchical structures were fabricated for the first time using the high reactivity of isocyanate groups. It is convenient to control the size of hierarchical particulates and to tune surface roughness by adjusting the reaction time. Dual-sized surface roughness, which biomimics the surface topography of sticky superhydrophobic gecko feet, originates from well-defined cauliflower-like particulates that are covalently anchored to a telechelic hydroxyl-modified substrate. After modified with fluorinated azobenzene, the resulting coating shows a static water contact angle as high as 156.5°and high water adhesion. We assume that the densely packed nanoscale aggregates are the key contributor to the observed high water adhesion, presumably by generating large van der Waals forces from the large surface area in close contact with water droplet.