A thin coating of graphene nanoribbons in epoxy has proven effective at melting ice on a helicopter blade.

The coating, developed by the lab of James Tour, professor of computer science and of materials science and nanoengineering at Rice University, may be an effective real-time de-icer for aircraft, wind turbines, transmission lines and other surfaces exposed to winter weather.

Graphene nanoribbons, produced by unzipping nanotubes, are highly conductive. As such, rather than trying to produce large sheets of expensive graphene, Tour's lab determined that nanoribbons in composites would interconnect and conduct electricity across the material with much lower loadings than traditionally needed.

In lab tests, the nanoribbons comprised no more than 5% of the composite. A helicopter manufacturer supplied a rotor blade and researchers spread a thin coat of the composite on a segment, then replaced the thermally conductive nickel abrasion sleeve used as a leading edge on the rotor blade. They were able to heat the composite to more than 200 degrees Fahrenheit.

When a small voltage was applied, the coating delivered electrothermal heat—called Joule heating—to the surface, which melted the ice. The lab succeeded in melting one-centimeter-thick ice on a static helicopter rotor blade in a minus-4-degree Fahrenheit environment.

A graphene nanoribbon-infused epoxy removes ice through Joule heating. Image credit: The Tour Group. For wings or blades in motion, the thin layer of water that forms first between the heated composite and the surface should be enough to loosen ice and allow it to fall off without having to melt completely, Tour says.

“Applying this composite to wings could save time and money at airports where the glycol-based chemicals now used to de-ice aircraft are also an environmental concern,” Tour says.

As a bonus, he adds, the coating—which remains robust in temperatures up to nearly 600 degrees Fahrenheit—may also help protect aircraft from lightning.