First there was Gorilla Glass, used to make tougher screens for iPhones. Now there's glass that has no glare and doesn't get wet or retain fingerprints. It's described in a paper in the journal ACS Nano and was invented by a group at MIT, including mechanical engineering graduate students Kyoo-Chul Park and Hyungryul Choi.
With most glass screens, there is a coating spread over the surface to prevent smudges and keep it dry. But this glass is different. Instead of a coating, the structure of the glass itself was changed. It's shaped like tiny cones, each one 200 nanometers wide at the base and about 1,000 nanometers tall.
The effect is to keep water — and a lot of other things — from sticking to the surface. Tall cones might sound fragile, but at that scale they can actually handle quite a lot of force, including getting hit by raindrops, dust, grit and, of course, fingers.
Making the glass didn't require any radical new technologies. The technique is adapted from the semiconductor industry, where surfaces are coated with several thin layers and then etched away to make a particular pattern. In the case of this glass, successive etchings leave the cones behind.
This kind of glass can do a lot of good for touch-screen smartphones and tablets by keeping them clean, smudgeproof and glare-resistant. But it could also work well in other places, such as solar cells, which lose efficiency whenever they get dusty or dirty. Repelling water would help keep the dirt off. The lack of glare would also help, as the light would get to the power-producing part of the cell and no longer simply be reflected back.
Credit: Kyoo-Chul Park and Hyungryul Choi, MIT