During winter, planes are doused with large amounts of de-icing fluids before they take to the skies. However, most of these glycol-based fluids are washed away during take-off, ending up in rivers and streams. The researchers, from the University of Illinois Chicago (UIC), have developed more than 80 different ice-resistant coatings in the form of creams, gels and emulsions that are designed to withstand the shearing forces of take-off and which are also biofriendly if they do wash into waterways.
“We questioned the lifetime of the cryoprotectants and looked at new ways to increase their effectivity,” said Sushant Anand, UIC assistant professor of mechanical engineering.
“Glycols dissolve very fast in the water and get washed away before the plane takes off, and it’s a serious problem that costs hundreds of millions of dollars - most of which literally ends up in the drain. We thought, why not improve such chemicals themselves, and make alternatives that can last longer while being more biofriendly. And that is what we ended up doing.”
Described in Advanced Materials, the ‘icephobic’ coatings are phase change material-based formulations that create a lubricating surface layer that is both slippery and non-freezing. According to the researchers, the coatings can be easily applied to metals, glass and plastic without any preconditioning or surface treatments. The gels in the family are also transparent, vital for applications such as cockpit and car windscreens, runway lights or windows.
“Our coatings are an all-in-one package which can delay formation of frost for extended hours and simultaneously cause any ice formed on its surface to easily shed off by a gentle breeze or simple substrate tilting,” said Rukmava Chatterjee, a UIC PhD student who worked with Anand on the research.
As well as the obvious applications in transport and buildings, the UIC engineers believe their ice-resistant coatings could one day be used to prevent crops from being lost to harsh frosts, though much more research would be required to establish the safety of that process.
“There is great potential in these materials for many applications, and I think the day when commercial versions of our materials come out just got closer,” said Anand.
“Since our anti-icing sprays are bio-friendly and anti-bacterial, we even think there is a potential to use them in agriculture to prevent crops from being ruined by severe frost. But that is a pipe dream, and we need to do more studies to see if there will be any long-term adverse effect on the plants.”
A worldwide patent application titled Compositions and Methods for Inhibiting Ice Formation on Surfaces has been filed by UIC’s Office of Technology Management.