Tag Archives: penguin feathers

McGill University’s proposed anti-icing technology inspired by penguin feathers

An October 24, 2022 news item on Nanowerk announces new research from McGill University (Montréal, Canada),

Ice buildup on powerlines and electric 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 is on wind turbines, electric towers, drones, or airplane wings, dealing with ice buildup typically depends on techniques that are time consuming, costly and/or use a lot of energy, along with various chemicals.

But, by looking to nature, McGill researchers believe that they have found a promising new way of dealing with the problem. Their inspiration came from the wings of Gentoo penguins who swim in the ice-cold waters of the south polar region, with pelts that remain ice-free even when the outer surface temperature is well below freezing.

An October 24, 2022 McGill University news release, which originated the news item, provides more detail, Note: A link has been removed,

“We initially explored the qualities of the lotus leaf, which is very good at shedding water but proved less effective at shedding ice,” said Anne Kietzig, who has been looking for a solution for close to a decade. She is an associate professor in Chemical Engineering at McGill and the director of the Biomimetic Surface Engineering Laboratory. “It was only when we started investigating the qualities of penguin feathers that we discovered a material found in nature that was able to shed both water and ice.”

Fine wire mesh replicates water-shedding and ice-shedding qualities of feathers

“We found that the hierarchical arrangement of the feathers themselves provides water-shedding qualities, while their barbed surfaces lower the adhesion of ice,” explains Michael Wood, a recent PhD graduate who worked with Kietzig, who is one of the co-authors on a new paper in ACS Applied Material Interfaces. “We were able to replicate these combined effects through a laser-machined woven wire mesh.”

Kietzig adds, “It may seem counter intuitive, but the key to ice shedding is all the pores of the mesh which draw water in under freezing conditions. The water in these pores is the last to freeze, creating cracks when it expands, much like you see in the ice cube trays in your freezer. We need such little force to remove ice from our meshes because the crack in each of these pores easily snakes along the surface of those woven wires.”

Promising results from early tests

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

“Given the number of regulations in place in passenger aviation and the risks involved, it is unlikely that airplane wings will ever be simply wrapped in metal mesh,” adds Kietzig. “It is, possible, however, that the surface of plane wings may one day incorporate the kind of texture that we are exploring, and that de-icing will occur thanks to a combination of traditional de-icing techniques working in concert in wing surfaces that incorporate surface texture inspired by penguin wings.”

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

The image on the left shows the microstructure of a penguin feather (the 10 micrometer closeup of the inset is the equivalent of 1/10th of the width of a human hair, to give a sense of scale) Those barbs, and barbules are branches off the feather’s central stem. The ‘hooks’ serve to attach individual feather hairs together into a mat. On the right is the stainless-steel wire cloth that the researchers decorated with nanogrooves that copy the hierarchy of the penguin feather structure (wire-like with nanogrooves on top). [downloaded from https://www.mcgill.ca/newsroom/channels/news/penguin-feathers-may-be-secret-effective-anti-icing-technology-342980]

Here’s a link to and a citation for the paper,

Robust Anti-Icing Surfaces Based on Dual Functionality─Microstructurally-Induced Ice Shedding with Superimposed Nanostructurally-Enhanced Water Shedding by Michael J. Wood, Gregory Brock, Juliette Debray, Phillip Servio, and Anne-Marie Kietzig. ACS Appl. Mater. Interfaces 2022, 14, 41, 47310–47321 DOI: https://doi.org/10.1021/acsami.2c16972 Publication Date: October 4, 2022 Copyright © 2022 American Chemical Society

This paper is behind a paywall.

Ice-free materials courtesy of penguins

The Humboldt penguin’s feathers don’t allow ice to form and a team of scientists have figured out why according to a Feb. 24, 2016 news item on Nanotechnology Now,

Humboldt penguins live in places that dip below freezing in the winter, and despite getting wet, their feathers stay sleek and free of ice. Scientists have now figured out what could make that possible. They report in ACS’ Journal of Physical Chemistry C that the key is in the microstructure of penguins’ feathers. Based on their findings, the scientists replicated the architecture in a nanofiber membrane that could be developed into an ice-proof material.

A Feb. 24, 2016 American Chemical Society (ACS) news release on EurekAlert, which originated the news item, provides a bit more detail,

The range of Humboldt penguins extends from coastal Peru to the tip of southern Chile. Some of these areas can get frigid, and the water the birds swim in is part of a cold ocean current that sweeps up the coast from the Antarctic. Their feathers keep them both warm and ice-free. Scientists had suspected that penguin feathers’ ability to easily repel water explained why ice doesn’t accumulate on them: Water would slide off before freezing. But research has found that under high humidity or ultra-low temperatures, ice can stick to even superhydrophobic surfaces. So Jingming Wang and colleagues sought another explanation.

The researchers closely examined Humboldt penguin feathers using a scanning electron microscope. They found that the feathers were comprised of a network of barbs, wrinkled barbules and tiny interlocking hooks. In addition to being hydrophobic, this hierarchical architecture with grooved structures is anti-adhesive. Testing showed ice wouldn’t stick to it. Mimicking the feathers’ microstructure, the researchers developed an icephobic polyimide fiber membrane. They say it could potentially be used in applications such as electrical insulation.

The researchers have provided an image illustrating their work,

[downloaded from http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.5b12298]

[downloaded from http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.5b12298]

Here’s a link to and a citation for the paper,

Icephobicity of Penguins Spheniscus Humboldti and an Artificial Replica of Penguin Feather with Air-Infused Hierarchical Rough Structures by Shuying Wang, Zhongjia Yang, Guangming Gong, Jingming Wang, Juntao Wu, Shunkun Yang, and Lei Jiang. J. Phys. Chem. C, Article ASAP DOI: 10.1021/acs.jpcc.5b12298 Publication Date (Web): February 3, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.