New de-icing system for planes takes cue from poisonous frogs

File photo.

File photo.  (REUTERS/Carlos Jasso )

Although spring is finally here, the nightmare of winter flight delays is still fresh in many frequent flyers’ minds. However, these delays could soon become a thing of the past, and we have poisonous frogs to thank. Researchers from Arizona State University believe they have found a way for plane wings to de-ice themselves by secreting anti-freeze, much in the same way a poisonous dart frog’s skin secretes a toxin when threatened.

ASU’s Konrad Rykaczewski has been working on anti-icing surfaces since 2012. Currently, antifreeze is sprayed down on airplane wings to prevent ice buildup, but the process is expensive, wasteful, and harmful to the environment. It’s also very time-consuming, causing delays that can only get worse if an airport runs out of the glycol and water mixture. Looking to get around these problems, Rykaczewski began working to make a system that could minimize the use of antifreeze.

“There are a few commercial examples of textured surfaces that are soaked in antifreeze, but by itself that wouldn't do much to reduce antifreeze use on airplanes in flight,” he told “Roughly around that time I was traveling to Panama and got to see the poison dart frog ­­­– that's a strawberry one, I believe – in the wild.”

Rykaczewski was intrigued by the system where the poison dart frog secreted toxin through its skin, in which an outer layer is exposed to the environment while an inner layer releases the poison when danger is present.

“The functionality of poison-release on demand was exactly what I wanted to do with antifreeze, and having a two-layer skin instead of a single textured layer was a clever way to do that.”

For airplanes, two paper-thin layers would be sprayed onto the wing of the plane. An outer layer would then be exposed to the elements while the inner layer would be infused with antifreeze. With the outer layer freezing over, the pores would fill up with ice and would then come in contact with the antifreeze. This would melt the ice. The release of antifreeze would be automatic.

“It took about year of work in lab to show that the idea has merit,” Rykaczewski added. “We added a twist with two layers having varying wetting properties: the top one somewhat gets temporarily switched when frost or condensate is on it to release the antifreeze.”

A syringe with a pump could be installed for larger planes or longer flights to make sure there would be enough antifreeze required for the trip.

While experts have praised the work of Rykaczewski and his team for their novel approach and ingenuity, some remain critical, saying that the new technology could change wing surface dramatically and unintentionally alter a plane’s in-flight performance. Rykaczewski said that while this scenario would surprise him, he couldn’t rule it out.

“[The] weeping wing system floods airplane wings with antifreeze during flight and planes have no issue flying. The exterior superhydrophobic texture we are proposing consists of very small nano/micro-bumps– that's smoother than mirror polished metal,” he said. “So I would be surprised if the texture would have a dramatic impact on airflow, but again, it’s a complex system and I can't rule out some negative interference.”

So how long until we can finally say good-bye to these ice-caused flight delays? According to Rykaczewski, it may only be a few years, with the team focusing on creating an “optimal arctic frog skin” before concentrating on cost and durability. For testing, he said they’ll start with arctic drones before moving to planes.

“For UAVs [Unmanned Aerial Vehicles], weight requirements are a big issue, so having a way to allow them to fly in very bad weather with only a small weight addition could be very beneficial,” Rykaczewski said. “Think, for example, of rescue missions in snow storms, etc.” 

Rykaczewski’s study was recently published in the journal Advanced Materials Interfaces.