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24 GROUND SUPPORT WORLDWIDE JUNE/JULY 2016 PRODUCT PROFILE A layer of conductive, atom-thin graphene nanoribbons on the surface of an aircraft has been found to repel water and ice at temperatures above 7 degrees Fahren- heit. Below that level, a small voltage heats up the graphene nanoribbons and ice slides right off the surface through a process called Joule heating. The conductive nanoribbons, each just a few microns long, create a "resistive barrier" and heat whatever surface they're attached to. "Joule heating is what happens on your back windshield when you fip the switch," James Tour, professor at Rice University, says. "You're applying a voltage across these wires and they're heating, that's how your back window in your car deices." Car manufacturers don't use Joule heating on front windshields, obviously, because the wires obstruct the driver's vision. The nanoribbon tech- nology in the Rice studies creates a transparent flm, they'll even work on glass. The electronics, Tour says, are dead simple. Two electrodes at the base of the flm complete the circuit and the resistance from the graphene generates heat. "These act as little resistors," Tour says. "It's just that you have billions and billions of them across these junction points and you don't see them, but that's where the heat is generated." The nanoribbon flm, which can be sprayed on or built into materials, requires no power as a passive deicing solution when temperatures are above 7 degrees Fahrenheit. No voltage is neces- sary. Theoretically, below that threshold, a ramp agent or pilot only has to fip a switch when the aircraft is connected to ground power to deice the entire aircraft. "Applying 40 volts to the flm brought it to room temperature, even if the ambient temperature was 25 degrees below zero," Mike Williams, a senior media relations specialist at Rice University's Offce of Public Affairs, wrote announcing the latest developments in late May. "Ice allowed to form at that temperature melted after 90 seconds of resistive heating." Economic and Environmental Impact The potential for graphene, a single-atom thick sheet of carbon, deicing has two main advantages for ground handlers. First, the diminishing role of deicing trucks. The graphene coating is likely going to be built into aircraft, according to Tour. A sheet of nanoribbons can be applied in a number of ways including through polyethylene paint or in an epoxy, but the most likely solution is that the tech- nology becomes a part of future aircraft designs. "It would be part of the fller, part of the mate- rial that's used to make the composite," Tour says. "So, as long as the composite is there the nanorib- bons are there." Second, the environmental comparison is staggering. There's no need for deicing fuids and therefore no dangerous chemicals pouring onto or off of aircraft. "There is no environmental impact in the sense that there's nothing spilling off the wing," Tour says. "It's not like you have mountains of ethylene glycol or propylene glycol going down into the drainage systems." A series of studies by researchers at Houston's Rice University, paired with Lockheed Martin, have developed technology that passively deices aircraft at temperatures as low as -14 degrees Celsius. Now looking to implement the technology, Rice researches are ready to change the industry. By Alex Wendland The Atomic-Level Future of Deicing is Almost Here Rice scientists have modifed their graphene- based de-icer to resist the formation of ice well below freezing. The robust flm is intended for use in extreme environments as well as on aircraft, power lines and ships. The Tour Group