A new class of coatings that sheds ice effortlessly from even large surfaces has moved researchers closer to their decades-long goal of ice-proofing cargo ships, airplanes, power lines and other large structures.
The spray-on coatings, developed at the University of Michigan, cause ice to fall away from structures – regardless of their size – with just the force of a light breeze, or often the weight of the ice itself. A paper on the research is published in Science.
In a test on a mock power line, the coating shed ice immediately.
The researchers overcame a major limitation of previous ice-repellent coatings – while they worked well on small areas, researchers found in field testing that they didn’t shed ice on very large surfaces as effectively as they had hoped. That’s an issue, since ice tends to cause the biggest problems on the biggest surfaces – sapping efficiency, jeopardizing safety and necessitating costly removal.
They cleared this hurdle with a “beautiful demonstration of mechanics.” Anish Tuteja, an associate professor of materials science and engineering, described how he and his colleagues turned to a property that isn’t well-known in icing research.
“For decades, coating research has focused on lowering adhesion strength – the force per unit area required to tear a sheet of ice from a surface,” Tuteja said. “The problem with this strategy is that the larger the sheet of ice, the more force is required. We found that we were bumping up against the limits of low adhesion strength, and our coatings became ineffective once the surface area got large enough.”