MIT Engineers Design Fog-Free, Water-Repellent, Anti-Glare Glass
Perfect Bead Blue-dyed water droplets sitting on a transparent nanotaper surface (left) and on flat glass (right), eachplaced on top of printed black letters. The insets are top views of the same two surfaces. Hyungryul Choi and Kyoo-Chul Park
A new type of nano-structured glass can bounce water and dirt off its surface, cleaning i...tself and preventing fogging, according to MIT researchers. It eliminatesglare, too, allowing light to penetrate with pure clarity. It could be used for anything from solar panels to future car windshields to new gadget screens.
The superhydrophobic glass shares some properties with the super-waterproof fabric coating we learned about this week, and it, too, is a feat of nano-engineering. But instead of a waterproof coating, it earns its special properties through a special etching process. Kyoo-Chul Park, Hyungryul Choi and colleagues drew inspiration from nature, including zebra plants, which contain conical structures that repel water. They developed a method to embed an array of steeply angled cones on the surface of glass.
Using techniques from the semiconductor industry, the team coated a glass surface with several layers of material that they then etched away according to a specifiedpattern. The nanostructured cones are 200 nanometers at the base and about a micron high.
Initially, it’s water-loving, but a simple vapor deposition process renders the material hydrophobic, the researchers say . The coating is not only completely transparent, but reduces glare, too. To test its waterproof capabilities, the team poured a droplet of water on the surface, filmed it with a Phantom high-speed camera and watched it form an almost perfect spherical bead.
There are plenty of applications for such a self-cleaning, water-repelling surface, not the least of which is solar panels, which are only as effective as they are clean and clear. Dirt and crud can block the photovoltaic cells’ ability to capture sunlight, and the reflective properties of glass direct some sunlight away from the cells, especially when the sun is at a sharp angle relative to the glass. But this new surface coating would eliminate all those problems, the researchers say.