This easily applied, highly transparent, superhydrophobic and superoleophobic coating makes glass and paint and a variety of surfaces self-cleaning. Several products on the market claim to repel water; this spray achieves superhydrophobicity and superoleophobicity, repelling water, oil, and dirt so that surfaces stay clean. University of Florida researchers have developed a highly hydrophobic alumina nanoparticle spray, easy to apply even to large areas, that causes water droplets to bounce from surfaces on contact, leaving them completely dry. The coating is anti-corrosive and anti-icing and can be used to protect important machinery such as circuits and grids or added into paints or countertop substrates to repel water, oily liquids, and organic solvents. By using surface physics not surface chemistry, scientists can vary the thickness of the alumina coating to best suit the material being repelled. A coating of 200-300 nanometers repels water, is highly transparent, and can be applied to surfaces that require high visibility, such as windshields, architectural glass, and device displays, to keep them clean. When a coating thickness of 1-100 micrometers is applied, the resulting surface is opaque and both superhydrophobic and superoleophobic.
Superhydrophobic and superoleophobic alumina coating for glass and other surfaces
The spray-on coating -- containing hydrophobic alumina nanoparticles -- gives surfaces a contact angle of 150 degrees so that water or oily droplets bounce off immediately, leaving the surface dry and clean. When added to paint or other substrates, those substances become superhydrophobic and superoleophobic. When coated with the spray, glass remains highly transparent with visible transmittance reaching as high as 90 percent. Though applications include water repellent windshields, easy-cleaning windows, or easy-cleaning device displays, the spray can be used on numerous substrates to make them water and oil repellent. The spray is fairly easily used for a large area application.
