Penguin feathers may be the secret to effective anti-icing technology | Newsroom

Ice build-up on power lines and power towers brought the northern US and southern Canada to a standstill during the Great Ice Storm of 1998, leaving many in the cold and dark for days and even weeks. Whether it’s wind turbines, power towers, drones or airplane wings, dealing with ice build-up usually depends on time-consuming, expensive and/or energy-intensive techniques, along with various chemicals. But by turning to nature, McGill researchers believe they have discovered a promising new way to tackle the problem. Their inspiration comes from the wings of Gentoo penguins, which swim in the icy waters of the southern polar region, with skins that remain ice-free even when the outside surface temperature is well below freezing.

“We first studied the qualities of the lotus leaf, which is very good at separating water, but it turned out to be less effective at separating ice,” said Ann Kietzig, who has been searching for a solution for nearly a decade. She is an Associate Professor of Chemical Engineering at McGill and Director of the Biomimetic Surface Engineering Laboratory. “It wasn’t until we started researching the properties of penguin feathers that we discovered a material found in nature that can separate water and ice.”

The image on the left shows the microstructure of a penguin feather (the 10 µm close-up of the inset is the equivalent of 1/10th the width of a human hair to give a sense of scale) These barbs and spines are branches from the central quill stem. The “hooks” serve to attach individual feather hairs to a backing. On the right is the stainless steel wire fabric that the researchers decorated with nanogrooves that replicate the hierarchy of penguin feather structure (similar to a wire with nanogrooves on top).

The fine wire mesh replicates the water and ice shedding qualities of feathers

“We found that the hierarchical arrangement of the feathers themselves provides water-shedding properties, while their barbed surfaces reduce ice adhesion,” explains Michael Wood, a recent Ph.D. ACS Application Materials Interfaces. “We were able to reproduce these combined effects using a laser-processed woven wire mesh.”

Kietzig adds, “It may seem counterintuitive, but the key to ice shedding is all the pores of the web that draw water in under freezing conditions. The water in these pores freezes last, creating cracks as it expands, similar to what you see in ice trays in the freezer. We need so little force to remove the ice from our nets because the crack in each of these pores easily curls over the surface of these woven wires.

Promising early test results

The researchers performed wind tunnel tests on surfaces covered with steel mesh and found the treatment to be 95% more effective in resisting ice build-up than unwrapped polished stainless steel sheet. Because no chemical treatments are involved, the new approach provides a potential maintenance-free solution to ice build-up on wind turbines, power towers and power lines, as well as drones.

“Given the number of regulations in place in passenger aviation and the associated risks, it is unlikely that airplane wings will ever simply be wrapped in metal mesh,” adds Kietzig. “However, it is possible that the surface of aircraft wings will one day include the type of texture we are investigating, and that de-icing will occur due to a combination of traditional de-icing techniques working together in wing surfaces that incorporate wing-inspired surface texturing of a penguin.”

Although more research is needed, the results so far are promising.

Learning

“Stable Anti-Icing Surfaces Based on Dual Functionality – Microstructure Induced Ice Detachment with Superimposed Nanostructure Enhanced Water Detachment” by Michael J. Wood, Gregory Brock, Juliette Debre, Philippe Servio, and Anne-Marie Kietzig in ACS Appl. Mater. Interfaces

https://doi.org/10.1021/acsami.2c16972

For McGill University

Founded in Montreal, Quebec, in 1821, McGill University is Canada’s top-ranked medical doctoral university. McGill is consistently ranked as one of the top universities, both nationally and internationally. It is a world-renowned institution of higher education with research activities spanning three campuses, 11 faculties, 13 professional schools, 300 study programs and over 40,000 students, including more than 10,200 undergraduates. McGill attracts students from over 150 countries worldwide, with its 12,800 international students making up 31% of the student body. Over half of McGill students say their first language is other than English, including approximately 19% of our students who say French is their first language.

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