Spray-On Coating May Ease Icing Problems

FRIDAY, MARCH 25, 2016

Research is underway on a durable, inexpensive ice-repellent coating developed with airplanes, oil rigs, power lines and other industrial machinery or structures in mind.

Researchers at the University of Michigan may have developed a coating alternative to expensive chemical melting agents and labor-intensive scrapers and hammers.

Led by Anish Tuteja, associate professor of materials science and engineering, the researchers created a spray-on coating they claim makes ice slide off equipment, airplanes and windshields with “only the force of gravity or a gentle breeze.”

The new coating could benefit energy, shipping and transportation industries in cold climates where ice is prevalent, they said.

The researchers also think there are commercial uses, notably in freezers that depend on complex defrosting systems that use high amounts of energy.

Their work is detailed in a new paper published in the journal Science Advances.

A New Approach

Using a mixture of common synthetic rubbers, the formula departs from prior approaches that created surfaces that were either slippery or water-repellent. The team found that rubbery coatings, even though they weren’t water-repellant, worked best at shedding ice.

"Researchers had been trying for years to dial down ice adhesion strength with chemistry, making more and more water-repellent surfaces," said Kevin Golovin, a doctoral student in materials science and engineering. "We've discovered a new knob to turn, using physics to change the mechanics of how ice breaks free from a surface."

The researchers claim that shedding water wasn’t as important as interfacial cavitation, a phenomenon that posits that solid material stuck to rubbery surfaces behaves differently.

The researchers claim that shedding water wasn’t as important as interfacial cavitation, a phenomenon that posits that solid material stuck to rubbery surfaces behaves differently.

According to Golovin, two rigid surfaces, like ice and a windshield, can stick tightly together, requiring a great deal of force to break the bond between them. Because of interfacial cavitation, however, for a solid material stuck to a rubbery surface behaves differently, even a small amount of force can deform the rubbery surface, breaking the solid free, he explained.

"Nobody had explored the idea that rubberiness can reduce ice adhesion," Tuteja said. "Ice is frozen water, so people assumed that ice-repelling surfaces had to also repel water. That was very limiting."

According to the researchers, the new coatings withstood a variety of tests, including salt spray corrosion, peel tests, high temperatures, mechanical abrasion, and hundreds of freeze-thaw cycles.

Numerous Applications

The team has designed hundreds of ice-repelling formulas for a variety of uses. Some formulas are smooth to the touch, some are rough. Some shed water, some don’t.

By altering the smoothness and rubberiness of the coating, researchers say they can fine-tune the degree of ice repellency and durability. Softer surfaces tended to be more ice repellant but less durable; harder surfaces, more durable but less ice repellant, the said.

"An airplane coating, for example, would need to be extremely durable, but it could be less ice-repellent because of high winds and vibration that would help push ice off," Golovin said.

"A freezer coating, on the other hand, could be less durable, but would need to shed ice with just the force of gravity and slight vibrations. The great thing about our approach is that it's easy to fine-tune it for any given application."

Tuteja thinks that within a year the first commercial application of the coating will be in use, probably in frozen food packaging where sticking is often a problem. Other uses may take longer to bring to market.

"Using this technology in places like cars and airplanes will be very complex,” because of the stringent durability and safety requirements,” Tuteja said. “But we're working on it."

Program Support

The team received funding and assistance from U-M’s Michigan Translational Research and Commercialization (MTRAC) program, created to support new innovations that demonstrate high commercial potential. MTRAC is funded in partnership with the Michigan Economic Development Corporation's Entrepreneur and Innovation initiative, which focuses on establishing Michigan as the place to create and grow a business by providing high-tech startup companies with access to a variety of resources.

Additional funding came from the Office of Naval Research, Air Force Office of Scientific Research, National Science Foundation and Nanomanufacturing Program.


Tagged categories: Asia Pacific; Coating chemistry; Coating Materials; Coatings; Coatings Technology; Colleges and Universities; EMEA (Europe, Middle East and Africa); Latin America; North America; Research and development; Specialty Coatings; Transportation

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