The research, sponsored by the Concentrating Solar Power (CSP) Program of DOE’s Sunspot Initiative, is based on ORNL’s superhydrophobic technology.
CSP plants, typically located in deserts, use hundreds of thousands of large mirrors to reflect solar energy onto receivers for energy conversion. Routine cleaning via jet spraying and manual scrubbing, involving up to a million gallons of deionized water, is required to remove dirt and dust and maintain reflectivity. The cleaning poses challenges including high labor and water costs, competition with local communities for water, and environmental impacts of the runoff. In superhydrophobic coating, a nanostructure is applied to a hydrophobic surface, making it essentially impervious to wetting by water. ORNL researchers have determined superhydrophobic surfaces are also resistant to aqueous solutions and viscous liquids, such as mud, and many solid particles. ORNL’s unique coatings consist of particles suspended in polymeric binders and do not use conventional vacuum deposition or chemical etching techniques. This makes them potentially inexpensive and easily applicable on most surfaces using conventional spraying or painting methods.
Superhydrophobic surface surrounded by a layer of water on an untreated surface.
ORNL has demonstrated that transparent, self-cleaning coatings can be applied to small laboratory samples. In the first year, the project aims to develop self-cleaning coatings that are durable while optimizing optical transparency. Field testing of coating performance will be performed in the second year.
Multifunctional superhydrophobic coatings also impart resistance to corrosion, icing, and biofouling. They are promising for numerous energy-related applications, including overhead power cables, infrastructure, solar panels, airfoils, coastal and offshore power and structural equipment, and ship hulls.