Scientists Discover How Penguins Naturally De-Ice Themselves

November 27, 2015 | Joanne Kennell

Penguin, ice
Photo credit: ravas51/Flickr (CC BY-SA 2.0)

The secret could be used to prevent plane crashes.

Antarctic penguins may be one of the cutest animals on the planet — and they are always dressed for a special occasion.  Antarctica is the harshest continent on Earth — it is cold, with air temperatures that can plunge well below -40 degrees Fahrenheit, and winds blasting with speeds of 90 miles per hour or more.  In these extremely harsh conditions, penguins still hop in and out of the chilly water but, amazingly, ice never forms on their feathers.

Pirouz Kavehpour, a professor in the Department of Mechanical and Aerospace Engineering at UCLA, noticed this phenomena while watching a nature documentary, which got him really interested in how penguin feathers are able to keep from icing. "I noticed the penguins were coming out of very cold water, and sitting in very cold temperatures, and it was curious that no ice formed on their feathers," he said.

SEE ALSO: The Science Behind Antifreeze

Kavehpour, and Judy St. Leger, a world expert on penguins, along with their team, began studying Gentoo penguin feathers donated by San Diego Seaworld, using Scanning Electron Microscopy.What they found was that Gentoo penguin feathers have very tiny pores that trap air and make the surface hydrophobic (i.e. water-repellent).  In addition, these penguins produce preen oil by a gland near the base of their tail which coats the feathers in the oil, making the feathers superhydrophobic.

According to the researchers, on superhydrophobic surfaces, water droplets pretty much sit on the surface as a sphere, and this delays ice formation since heat can not easily flow out of the water droplet without a lot of surface contact.  The water droplets simply flow off the feathers before they have a chance to freeze.

water droplets on a feather
Droplets tend to form on hydrophobic surfaces. This formation reduces contact between the cold surface and the water. (Stock photo)

"Heat flow could be compared to traffic. If you have a freeway that turns into a tiny, two-lane road, the traffic will back up. Similarly, heat does not flow well from the large cross-section of the middle of the drop to the small cross-section where the drop makes contact with the feather," Kavehpour said.

The main focus of the research looked at the Gentoo penguins, who lives in Antarctica and the southern most parts of South America.  To determine if these properties are common to all penguins, the researchers decided to compare Gentoo feathers to feathers from the Magellanic penguin, who lives in warmer climates north of Chile, Argentina and Brazil.  It turns out that the feathers of warmer climate penguins do not have the small pores, and they also produce a different form of preen oil that is not as hydrophobic.

The research conducted on the superhydrophobic properties of penguin feathers can be used to solve ice problems we deal with today.  For example, ice that forms on airplane wings can alter the aerodynamic properties of the airplane and cause it to crash, and airlines spend a lot of money and time using chemical de-icers.  There are also many flight delays due to aircraft icing that cause stress to passengers.  

It may be possible, given what researchers have learned, to build exterior parts of planes with superhydrophobic surfaces.  In fact, this may be a cheaper option which lasts longer, and is also more environmentally friendly.

"It's a little ironic that a bird that doesn't fly could one day help airplane [sic] fly more safely," Kavehpour said.

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