Water-Repelling Metals

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The material's robustness will be key because of the high-performance applications that GE is targeting, says Gareth McKinley, a mechanical-engineering professor at MIT. He thinks that out of the two different approaches to making the superhydrophobic metal, altering the material surface itself would last longer. With a coating, he says, "there's a possibility that it's going to come off or flake off. So something intrinsic to the material will be more robust."

Blohm says that both approaches--roughening the metal or coating it with a textured material--might have their advantages, depending on how the material is used. "Most of the environments we're looking at with metals are rather harsh, whether it's temperature, moisture, corrosion, or other contaminants," she says. "So in some applications, you might choose textured metals that might be more robust, but in others, you might want to have the coating carry the performance with options to replace the coating."

The researchers are testing many different models of superhydrophobic metals. They are tinkering with the texture of the metals and coatings to see what works best in certain harsh environments. The material would eventually have to be tailored to the application, Blohm says. "If we feel good about [a material]--one we know that might be more expensive and maybe not robust enough for the environment, but we see performance in those model textures--then it's worth the investment," she says. "Then we'll work on making it manufacturable and robust in a specific environment."