Superhydrophobic Surfaces Made from Naturally Derived Hydrophobic Materials

Functional coatings that can achieve stable superhydrophobicity have the potential to significantly enhance a plethora of industrial applications ranging from building environmental control, phase change heat transfer, thermoelectric power generation, and hydrodynamic drag reduction. In order to create superhydrophobic surfaces, scientists have utilized a variety of surface structuring methods in combination with organosilane based alkyl and perfluorinated synthetic chemical coatings. Unfortunately, organosilane based alkyl and perfluorinated chemicals tend to be toxic, flammable, corrosive, difficult to dispose of, and damaging to the environment. Here, we develop two new methods to achieve superhydrophobicity using liquid phase deposition of cinnamic acid or myristic acid, both organic compounds derived from natural sources. By varying the liquid phase solution concentration, we develop deposition methods on scalable copper oxide microstructured surfaces capable of achieving apparent advancing contact angles as high as 154° and 165° for cinnamic and myristic acid, respectively, with low contact angle hysteresis (<15°). To demonstrate superhydrophobic performance, we utilize high speed optical microscopy to show stable coalescence induced droplet jumping during atmospheric water vapor condensation. This study presents a novel avenue for safer and more environmentally friendly fabrication of superhydrophobic surfaces for energy and water applications.