SEAS Team Develops Ice-Repelling Technology

A new technology to prevent ice and frost from forming on surfaces has been developed by a team of Harvard researchers led by engineering professor Joanna Aizenberg. The technology, known as Slippery Liquid Infused Porous Surfaces—SLIPS, for short—even works in humid and high-pressure conditions, where ice has historically been difficult to repel.

Philseok Kim, a School of Engineering and Applied Sciences researcher on Aizenberg’s team, said that the discovery would have a large impact on any industry that needs to stave off ice.

“We will see a lot less ice or frost building up on the surfaces we want to keep ice-free,” Kim wrote in an email. “We anticipate huge energy savings associated with defrosting and improved safety in aircraft and many other infrastructures.”

According to Kim, previous research into ice-repellent surfaces has focused on the lotus effect—the lotus leaf’s ability to repel water thanks to its complex, three-dimensional surface.

Kim said that just two years ago, Aizenberg’s team was working on lotus-inspired surfaces. But these technologies proved ineffective in high humidity conditions, where the textures ended up attracting ice rather than repelling it.

In a press release announcing the new ice repellent, Aizenberg stated that the new surfaces would avoid this problem. According to Kim, SLIPS-coated surfaces achieve this effect in three major ways. Water vapor is kept away from the surface by a lubricating fluid, which also creates a surface so smooth that condensation will slide off as soon as it starts to form. Likewise, the surface is slippery for solids in the event that condensation does freeze.

Kim noted that this technology can also be used to repel substances besides ice, though this may lead to increased costs as the lubricant would require fluorination.

“If we are only concerned about water and ice, the coating can be much cheaper as it can be prepared from silicone lubricant that can be purchased in large quantities from already existing manufacturers,” Kim wrote.

—Staff writer Petey E. Menz can be reached at menz@college.harvard.edu.