A team of researchers from the University of Michigan may have finally found the answer to keeping car windshields from freezing through the use of an inexpensive coating system capable of repelling ice.
In a study featured in the journal Science Advances, Anish Tuteja, a professor of Materials Science and Engineering at UM, led his colleagues in developing a new spray-on formula that can protect car windshields, airplanes and other equipment from becoming frozen in ice.
The resulting material covers surfaces with clear, rubbery solution that allows ice formations to simply slide off of various objects with force from the wind or gravity.
Creating The Ice-Repellent Formula
While previous attempts have been made to develop water-repellent surfaces through chemistry, Tuteja and his team chose to examine the ice-repelling qualities of rubbery surfaces and focused their efforts in recreating these effects using a new coating formula.
The researchers looked at the properties of various synthetic materials, such as polydimethylsiloxane (PDMS), polymethylhydrosiloxane (PMHS) and silicone oil, and combined them to create the new spray-on product.
To test the ice-repelling properties of the formula, the team applied it on one half of a license plate and left the other half without any form of protection. They then exposed the plate to freezing rain overnight.
When they checked the license plate the following morning, they discovered that the half without any coating was covered in ice. The half that had the icephobic material also had ice formations on it, but they were easily sheared off.
Tuteja and his colleagues also tested the new formula on other materials such as glass panels.
Despite not being able to repel water, the rubbery coating was able to stop ice from setting on the surfaces because of a phenomenon known as interfacial cavitation. This pertains to the ability of rubbery surfaces to change forms even when exposed to small amounts of force, which effectively prevents ice from becoming tightly bonded to them.
The new formula can also help materials become more resistant to damage caused by ice. Surfaces that were covered in the icephobic coating showed improved durability even after being exposed to high temperatures, peel tests, mechanical abrasion, salt spray corrosion and repeated freeze-thaw cycles.
By adjusting the degree of rubberiness and smoothness of the icephobic coating, the researchers discovered that they make the material more durable and ice repellent. This gives the formula the flexibility it needs so that it can be applied to a wide range of surfaces.
Study co-author Kevin Golovin explained that the icephobic coating for an airplane would have to be much more durable compared to those for other surfaces. However, it could also be less ice-repellent because of the amount of vibration and strong winds it would encounter during a flight that could help shear off any ice formations.
Meanwhile, the coating for a freezer could be fine-tuned to become less durable, though it would have to depend on slight vibrations and the force of gravity in order to shed ice from its surfaces, Golovin said.
Tuteja and his team have already come up with hundreds of variations for their ice-repelling formula to fit different needs.