Are penguin feathers the new anti-freeze?

Photo by Cornelius Ventures on Unsplash

Researchers have developed a chemical-free solution to ice build-up and it is likely to ruffle some feathers at the anti-freeze factory.

Whether on wind turbines, electric towers, drones, or airplane wings, ice build-up can be dangerous and costly to fix. Plus, tackling ice often requires large amounts of energy and the use of toxic chemicals. Looking to nature, researchers from McGill University in Montreal, Canada, have found a possible solution by creating a mesh that replicates water-shedding and ice-shedding qualities of feathers.

“When we started investigating the qualities of penguin feathers that we discovered a material found in nature able to shed both water and ice.”

Anne Kietzig, McGill University

The researchers studied the structure of the wings of Gentoo penguins, whose feathers remain ice-free even when the outer surface temperature is well below freezing, in the ice-cold waters of the south polar region which is their home.

What's so special about penguin feathers?

Penguin feathers are highly specialised. They are short, broad, and closely spaced, which helps keep water away from the skin. Tufts of down on the shafts increase the insulating properties of the feathers.

“We found the arrangement of the feathers themselves provides water-shedding qualities, while their barbed surfaces lower the adhesion of ice. We were able to replicate these combined effects through a laser-machined woven wire mesh,” explained Dr Michael Wood, co-author of the study.

The mesh - which mimics the form of the penguin’s feather structure - is studded with pores which draw in water under freezing conditions. The water in these pores cracks as it expands, meaning less ice is able to build-up and very little force is needed to remove any remaining ice from the mesh.

The image on the left shows the microstructure of a penguin feather. The inset image is a closeup showing the barbs and barbules that branch off the feather’s central stem, attaching individual feather hairs together into a mat. On the right is the stainless-steel wire cloth marked with nanogrooves that mimic the penguins' feather structure. Image: McGill

The researchers carried out wind-tunnel testing of surfaces covered by the steel mesh and found the treatment was 95% more effective at resisting ice build-up than a sheet of polished stainless steel. Because there are no chemical treatments involved, the new approach provides a potentially maintenance and chemical-free solution to ice build-up on wind turbines, electric towers and power lines as well as drones.

“It is possible the surface of plane wings may one day incorporate the kind of texture we are exploring, and de-icing will occur thanks to a combination of traditional de-icing techniques working in concert with wing surfaces that incorporate surface texture inspired by penguin wings," added Kietzig.