Hydrophobic coatings on the surface of objects help keep medical devices sterile, help de-icing aircraft wings, and keep solar panels clean. Thanks to the nanostructures, these coatings allow water droplets to slide efficiently, thus avoiding the build-up of dirt, germs or other contaminants. However, one of the major drawbacks of the current ordinary nanocoating is the poor scratch resistance. The good news is that scientists at the University of Alto in Finland and the China University of Electronic Science and Technology have developed a special waterproof armor.
Cross-sectional (from: Aalto University)
Typically, nano-hydrophobic coatings apply “forest-like” structures protruding on substrates, but unfortunately these structures are quite fragile and can wear out quickly over time, causing that part of the area to lose hydrophobicity quickly.
But scientists at the University of Aalto in Finland and the China University of Electronic Science and Technology have developed a special coating, claiming to be an effective way to solve such problems.
The process involves etching the nano-inverted pyramid-shaped honeycomb pattern mesh to a substrate such as metal, glass or ceramics, and then coating ultra-hydrophobic chemical coatings into the interior of the pyramid.
That way, when a tool such as a sharp blade or sandpaper crosses the armored surface, the ridge between the cones prevents it from falling into the interior of the structure to protect the waterproof coating underneath.
In addition, the scientists specially treated the surface to withstand high-pressure water jets, extreme humidity, soaked in corrosive chemicals for hours, and baked for weeks at temperatures at 100 degrees C (212 degrees F).
Even after these rigorous tests, the new waterproof armor coating retains the super-hydrophobic properties of the surface.
Details of the study have been published in the recently published journal Nature, originally titled Design of the robust superhydrophobic Surfaces.
Professor Robin Ras, of the University of Alto, added: “We made honeycomb-coated armor with materials of different sizes and shapes, which have the advantage of being versatile with a wide variety of materials, giving us the flexibility to design a variety of durable, waterproof surfaces.”