A team of scientists at the University of Rochester in New York have created metal surfaces that repel water by “bouncing” it away. The technology could produce hygienic, easily-maintained devices that do not rust or ice up. The team reported their findings in the Journal of Applied Physics.
Other approaches to crafting a superhydrophobic surface have relied on coatings but this method uses an extremely powerful laser to permanently sculpt the metal’s surface.
The structures created by our laser on the metals are intrinsically part of the material surface,” said senior author Prof Chunlei Guo.
“The material is so strongly water-repellent, the water actually gets bounced off. Then it lands on the surface again, gets bounced off again, and then it will just roll off from the surface.”
The researchers demonstrated their work by covering some samples in dust from a vacuum cleaner. 10-15 water droplets left the metal surface completely clean and dry. Water droplets gathered the dust particles before being bounced away, making the metal “self-cleaning.”
The professor’s team achieved their results by etching parallel grooves into the metals, 0.1mm apart, using rapid pulses of a laser beam that are extremely strong but last just a few quadrillionths of a second.
It is hoped that the research will help make better devices for collecting rain water, or hygienic surfaces for medical purposes. But for that to happen the process would need to become cheaper-and much faster. It currently takes an hour to treat an inch of metal.