Superhydrophobic Metals And Energy Efficiency  

Technology Review has an article on some biomimicry style GE research into "superhydrophobic materials" which can result in more energy efficient turbines - Water-Repelling Metals.

Researchers at GE have come up with a way to treat metals so that they repel water. The extreme water-repelling property, called superhydrophobicity, means that water forms drops on the surface instead of spreading and sticking to it.

The advance builds on previous work that came out of GE's Global Research Center, in Niskayuna, NY. Two years ago, researchers showed that they could make Lexan--a widely employed plastic that's used to create CDs, iPods, aircraft windscreens, and car headlamps--water-repellant. They did this by chemically treating the surface to make it rough. The researchers have now demonstrated the same effect on metal surfaces.

Many other superhydrophobic materials have been demonstrated, but most have used some kind of plastic. Superhydrophobic metals open up many new applications, says Jeffrey Youngblood, a professor of materials engineering at Purdue University. "Metallic structures are more robust and can survive in harsher environments, allowing for their use in applications where plastic is infeasible, [such as in] planes, trains, automobiles, heavy machinery, and engines," Youngblood says.

GE has some ideas about how to use the materials. One possibility is in de-icing aircrafts. Ice buildup on engines due to condensation can be catastrophic. Right now, aircraft use heat to prevent ice, which requires power. De-icing on the ground, meanwhile, is done with de-icing fluids, which contain toxic chemicals; spraying aircraft with de-icing fluids on the ground also takes a lot of time. "It would be very desirable if we could . . . just be able to have a material on which ice didn't stick," says Margaret Blohm, advanced technology leader for the nanotechnology program at GE's Global Research Center.

Another application for the metals could be in gas and steam turbines. The superhydrophobic metals could reduce the buildup of moisture and contaminants on the turbines, increasing their efficiency and requiring fewer shutdowns for maintenance.

GE researchers have not published their work, and they declined to divulge much about their research achievements. But they do say that their inspiration comes from lotus-plant leaves, which have a nanocrystalline wax structure. On the leaf's surface are tiny wax crystals tens of nanometers wide, which hold water drops as almost perfectly spherical beads.