Blossoming technology: GE scientists imitate lotus plant, nano-treat metals to repel water

At GE Global Research in Niskayuna, scientiests have spent the past four years attempting to turn th
Margaret Blohm, GE Global Research’s advanced technology program leader in nanotechnology, demonstrates on texture-coated titanium how water if repelled with the use of hydrophobic metal technology.
Margaret Blohm, GE Global Research’s advanced technology program leader in nanotechnology, demonstrates on texture-coated titanium how water if repelled with the use of hydrophobic metal technology.

The lotus. For centuries in China, it has served as a symbol of liberation for the way the plant rises from muddy waters to still produce pure white blossoms.

“In the deep sequestered stream the lotus grows,” wrote the eighth-century Chinese poet Li Po. “Its glowing petals shade the clear autumn water/and its thick leaves spread like blue smoke./Alas! in vain its beauty excels the world.”

At GE Global Research in Niskayuna, the lotus — or at least its “thick leaves” — is receiving just as much praise from scientists. They have spent the past four years attempting to turn the lotus’ poetic qualities into nanotechnology products that could revolutionize GE’s energy, aviation and healthcare arms.

In a laboratory in GE’s sprawling research campus, Margaret Blohm last week demonstrated the reason for the conglomerate’s enthusiasm. She held a water dropper over a slab of titanium and let a few drops slip out.

‘How to Make Water Bounce’

To view a YouTube video posted by GE Global Research in which a drop of water bounces off a piece of super hydrophobic metal, click HERE.

Instead of splattering on the metal, the drops reformed as spheres upon impact and rolled off the surface, which had been nano-treated with a special ceramic coating. Just like a lotus leaf, which repels raindrops in like fashion, the metal was hydrophobic.

“This is why the lotus is this way. Nature isn’t dumb.  . . . That’s why the leaf evolves that way. It cleans itself,” said Blohm, GE Global Research’s advanced technology program leader in nanotechnology.

Blohm was referring to what botanists have dubbed “the lotus effect”: the way water forms drops on the plant’s leaves, cleaning their surface of dirt as they roll off them.

GE scientists want to apply the lotus effect to metals used in industrial products. Their ultimate goal is to increase the efficiency of wind and gas turbine blades and the fan blades of jet engines by reducing the amount of ice that forms on them. Lotus effect-based technology could also end up being applied to medical stents, implants and contact lenses.

The lotus effect research being conducted in Niskayuna is especially promising for GE Energy’s manufacturing operation in Schenectady. By devising ways to mass-produce specially abraded metals or coatings for turbines, GE could push deeper into renewable energy markets where cold weather has stood as a deterrent.

“Ice is just an unsolved problem,” Blohm said.

GE Energy earlier this month announced the milestone delivery of its 10,000th 1.5-megawatt wind turbine to a North Dakota wind farm. Over the past decade, the conglomerate said, GE wind turbines have been installed in 19 countries, accumulating 130 million operating hours and producing 78 gigawatts of renewable electricity.

“GE’s renewables business is constantly looking for ways to achieve higher

performance, reliability and efficiency for our wind products through technology enhancements,” said Dan Nelson, public relations manager for GE Energy in Schenectady.

“We are working closely with our colleagues at the Global Research Center in Niskayuna on various coatings and surfaces to enable wind turbines to operate more efficiently in many environments, including those more prone to colder, winter climates. Today, GE has over 10,000 1.5MW units in operation world wide and our focus is managing this fleet through proven performance and high reliability. Through multigenerational technology enhancements, such as superhydrophobic coatings, GE’s advanced wind technology can offer additional value for our customers and is a great example of how we can apply the expertise of our Global Research Center.”

Botanist’s insight

GE’s research into the lotus effect began with the published studies of German botanist Wilhelm Barthlott. Starting in the 1970s, Barthlott conducted groundbreaking research on lotus leaves, focusing on the their water-resistant qualities.

A closer look at the leaves’ surface reveals a series of peaks, like microscopic goose bumps. An even closer inspection found tiny fibers on those bumps. Together, those features create a type of air cushion.

“The water droplet is hardly touching any surface, so the water droplet thinks it’s sitting on air,” Blohm said.

Around 2004 — just two years after Blohm established an advanced nanotechnology program at GE Global Research — a scientist on her team presented Barthlott’s lotus effect research as holding promises for the conglomerate.

GE scientists in Niskayuna initially began examining ways the lotus effect could be applied to polymers. That research was geared for the conglomerate’s plastics and silicone divisions.

The scientists managed to replicate the lotus effect on plastic surfaces, raising the prospect of self-cleaning windows. But the scientists could not make the plastic durable enough to commercialize it.

The 2007 sale of GE Plastics, which had operations in Selkirk and Pittsfield, Mass., also put a damper on the lotus effect research in Niskayuna. A year earlier, GE also shed its Waterford silicone plant, which now is operated by Momentive Performance Materials.

“For GE without plastics, we started thinking what we could do with a surface like that. We looked across our businesses and brainstormed,” said Blohm.

Her research settled on catering their lotus effect research efforts to applications for GE Energy, GE Aviation and GE Healthcare.

On Nov. 13, a GE scientist posted a video on YouTube, showing the fruits of more than two years of lotus effect research. The clip on the online video-sharing Web site is titled “How to Make Water Bounce.”

The slow-motion video shows a drop of water landing on a piece of nano-treated metal. In about two weeks, the bouncing water clip has received over 150,000 views on YouTube, making it the 21st most popular science and technology video on the Web site this month.

In the video, a drop of water lands with a splash but then re-forms and actually bounces off the treated surface. The few much smaller fragmentary droplets that remain on the surface roll away.

“Ice would be a lot less likely to form [on the metal’s surface],” but even if it does form, it won’t stick as well,” Blohm said.

Simulation test

To test that theory, GE has constructed two wind tunnels in its Niskayuna facility to simulate the impact of water on nano-treated metals in cold-weather conditions.

The metals put through the miniature wind tunnels include steel, titanium, nickel and aluminum. Metals naturally attract water, and to make them hydrophobic, GE scientists treat them with special coatings or grate them with sandpaperlike materials.

Over the past three years, GE has submitted several patent applications regarding its super hydrophobic metal research. Niskayuna scientists this month received notice from the U.S. Patent and Trademark Office that it has begun reviewing one of their earliest patent applications.

GE is still years away from commercializing the hydrophobic metals, though it is currently drafting a patent for their manufacturing process. While GE refines industrial lotus effect applications, other companies are developing or have already debuted “self-cleaning” residential products based on similar nanotechnology. Among them is the Sto Corp.’s silicone exterior paint, called Lotusan.

In 1999, the Atlanta-based Sto released in Europe and later in North America Lotusan, which is highly resistant to dirt, mold and mildew.

A 2002 study found that Lotusan surfaces have 90 percent fewer germs than surfaces coated with conventional paints. Other researchers are looking at ways to make lotus effect bathroom mirrors, automobile paints, roof shingles and clothing.

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