Thanks to an innovative laser process, however, metal is getting its revenge.
University
of Rochester scientists Chunlei Guo and Anatoliy Vorobyev have
developed a technique using extremely precise laser patterns that
renders metals superhydrophobic: in other words, incredibly
water-repellent.
Imagine a much more
powerful Teflon -- except that Guo and Vorobyev's material isn't a
coating but part of the metal itself. Water actually bounces off the
surface and rolls away.
The
possibilities are many, Guo says. Kitchenware, of course. Airplanes: No
more worrying about de-icing, because water won't be able to freeze on
aircraft in the first place.
And
sanitation in poor countries, an idea close to the heart of the Bill
and Melinda Gates Foundation, which helped fund the project. Thanks to
the surface's repellent properties, it's essentially self-cleaning.
Ironically,
Guo was inspired by a project in which he and a team treated a variety
of materials to make them superhydrophilic -- that is, water-attracting.
"We
worked with a variety of materials -- not just metal but
semiconductors, glass, other things," he said. Even on a vertical
surface, "the effect was very strong. If I drop a drop of water on the
bottom of this surface, it would actually shoot up against gravity,
uphill. So that really motivated us to look into this reverse process."
In
their paper, the two compared the surface to that of a lotus leaf,
which has "a hierarchical structure containing a larger micro-scale
structure" and is superhydrophobic.
"Our structure sort of mimics, in some way, this natural (arrangement) of the lotus leaf," Guo said.
And
like the lotus leaf, because the laser-patterned metal is so
water-repellent, it has self-cleaning properties. In an experiment, Guo
dumped some household dust from a vacuum cleaner on a treated surface.
Just a few drops of water collected the dust, and the metal remained
dry.
In their work, the scientists used
platinum, titanium and brass as sample metals, but Guo says he believes
it could work for a wide variety of metals -- not to mention other
substances.
The process is still very
much of the lab. It took the scientists an hour to treat a
1-inch-by-1-inch sample and required extremely short bursts of the laser
lasting a femtosecond, or a millionth of a billionth of a second.
But
Guo is optimistic about ramping up the process for industrial use, and
he says the goal for the sanitation project is to "really push the
technology out" in the next two or three years.
And then?
"I do believe down the line we will be able to make it accessible to everyday life," he said.
Watch out, water.
The scientists' paper was published in the Journal of Applied Physics. The project was also funded by the U.S. Air Force Office of Scientific Research.
This article was taken from CNN
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