Absolute repulsive material created for all types of liquids.
Two researchers from UCLA, a division of UC Irvine University of California, Tingway Liu and Changjin Kim, developed a coating for any surface that makes them superhydrophobic — that is, it can repel any, even the most wetting fluids. The nanotechnological process changes the physical characteristics of the surface. Since this is not a chemical process, it can be used both for industrial purposes, for example, to slow down corrosion processes, and for the manufacture of household items, the same kitchenware.
In an interview with Phys.org, a professor in the field of mechanics and aeronautical engineering Changzhin Kim said: “In nature, some leaves under the microscope look“ hairy ”, thereby reducing the area of leaf contact with water droplets. Reducing the contact area means that the drop is held due to surface tension. Artificially created superhydrophobic surfaces are developed on the same principle, and in fact have microscopic irregularities on the surface of a hydrophobic material. ”
Many materials used now in the industry and in a life, possess water-repellent properties. However, liquids with lower surface tension, such as oil, still wet them, since such a small surface tension allows them to spread over the surface of materials. The surface, developed by researchers, resembles a forest of nails, located at distances of about 100 microns from each other, with caps with a diameter of less than 20 microns. The hats are not simple, they also have their own shape - around the perimeter of the cap there is a “skirt” about half a micrometer high, which hangs down from the cap. The angle between the skirt and the cap is 85 degrees. Being suspended on these "nails", a drop of liquid is 95% surrounded by air, and therefore easily kept by its own surface tension.
Thus, it is possible to repel surfaces not only water and oil, but also any, even the most wetting liquid, including perfluorohexane - a liquid with the smallest surface tension known to date. The coating was tested on glass, metal and polymer - and in all cases it turned out to be workable. Researchers believe that it will be possible to use such a coating in the open air, for example, on surfaces of cars and buildings. The coating does not degrade over time due to temperature changes and exposure to ultraviolet radiation. In addition, it can withstand temperatures up to 1000 degrees, and is not exposed to biological materials, which allows it to be used also in medicine.