Lab-Funded Transparent Coating Repels Water Published Nov. 21, 2008 By Molly Lachance AFOSR ARLINGTON, Va. -- A team of AFRL-sponsored researchers developed a transparent coating that causes water to bead up into drops and roll or bounce off the surface. This technology will help protect and sustain Air Force systems by preventing corrosion and reducing ice formation on optical elements and aircraft. The researchers are employing this emergent technology not only to repel water, but also to design a surface capable of drawing water from humid air. The new surface combines extremely water-repellent and water-absorbent areas to create the desired effect. Modeled after the Namib Desert beetle's unique biological capacity to extract moisture from its arid environment, this bioinspired technology could provide troops an energy-free method for collecting water in areas where resources are scarce. Producing and appling a coating with superhydrophobic--or super-water-repellent--properties required that researchers control coating roughness and surface chemistry on a small scale. Comprising researchers from the Brinker Nanostructures Research Group (University of New Mexico) and Sandia National Laboratories who were already known for their breakthroughs in aerogel thin-film processing, the team leveraged that earlier research in devising a simple way to deposit the coating on every contour of a given surface by spraying, spinning, and/or dipping. The team's simple modification of a chemical precursor reversed the shrinkage that typically occurs as a coating dries. The chemical alteration yields a substance that springs back, creating a nanoporous surface with superb water-repellant properties. The most recent advancement in this research is the ability to selectively pattern the coating and spatially control the wetting behavior for a desired application. The team's recent work has opened the door to new applications that exploit the way in which the coated surface interacts with liquid droplets. When water droplets roll along the coated surface, they pick up debris as they go. This property might enable the collection, concentration, and identification of aerosol-borne particles, such as anthrax. In addition, the research will likely transition to commercial use, aiding applications such as the protection of electronics and antiquities from water damage.