Saturday, January 24, 2015

Amazing super-hydrophobic materials

Automotive applications for new hydrophobic metal stagger the mind


Sometimes, like now, science is so awesome it just makes us laugh. The guys and gals in the white lab coats have come up with a laser-etching process to make metal so hydrophobic that water bounces off it. We don't mean the water slides off, we mean the surface is so repellent that the water hits it, flies up into the air, screams "Get me out of here!", and keeps bouncing until it reaches a less-repellent surface.

A team led including optics professor Chunlei Guo at the University of Rochester is responsible for the innovation. Guo said the team first developed a super-hydrophilic metallic surface a few years ago so attractive to water that water would run up, against gravity. Reversing the process, they found a way to etch patterns into metal at microscopic and nanoscale levels that water molecules will actively try to get away from. It makes Teflon look like a sponge. Another upside is that since the pattern is etched into the metal, it won't degrade like a chemical coating.

Potential uses include on airplanes to prevent icing and in sanitation to cut down on water requirements. Automotive possibilities include anything you don't want to get wet, or corrode. Yes, it's a long way from a tiny square of metal in a university lag to an industrial use; Guo never mentions how much the it would cost to scale the technique. You couldn't use it on painted panels, for instance, because they'd cover the pattern. Damage to the metal, like from dents or road debris, would also alter the pattern structure. But engine components and internal structures might make some hay with this.

There's a short video above with a demonstration of the metal, and a longer one below with Guo explaining how it came about.


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