It’s a truism that science can learn a lot from nature. But in the nanotechnology lab at GE Global Research headquarters in Niskayuna, N.Y. researchers are applying the lessons of plant leaves to high tech materials that can shed water, prevent ice from forming and even clean up oil spills by sopping up hydrocarbons but not water.
Water droplets only contact a small portion of the lotus leaf's surface.
These materials mimic the “lotus effect,” which describes the water repellency, or superhydrophobicity, of lotus leaves. On the micron scale, the leaf’s smooth surface appears as a rough coating, with fine hairs that allow only a small percentage of the water droplets to come into contact with the leaf.
“We found a whole new physics of water just from looking at water on a leaf,” says Margaret Blohm, the leader of the nanotechnology department.
The nanotechnology lab’s mission is, in essence, to reproduce the success of the Lotus leaf. They seek to create coatings that can keep unwelcome water and ice from airplane engines and keep water and contaminants from building up in gas turbines.
But it’s a new application, which combines water repellant qualities with an affinity for oil – that is, hydrophobic and oleophilic – that has the nanotechnology scientists most excited.
Ambarish Kulkarni and Margaret Blohm at the nanotechnology lab. Photo Chris New
To demonstrate what these qualities do in real life, Ambarish Kulkarni, a mechanical engineer at GE, dropped a small amount of oil into a flask of water. He then dipped a specially treated material into the flask and absorbed all of the oil.
Kulkarni said the material exploits the different surface tensions of oil and water, but exactly how it does that is a trade secret.
The applications for this technology abound.
The material could be fashioned into “huge, porous buoys,” to clean up oil spills in the water, Kulkarni said. It can also be used to improve the efficiency of oil separation in oil fields where water has been injected to increase well pressure.
The material is currently in the early stages of research but shows a lot of promise, Blohm said.
“If we hadn’t been intrigued by the lotus leaf, we never would have gone there,” she said.
See Kulkarni extract oil from water with nanomaterials: