During the Great Ice Storm of 1998, ice buildup on power lines and poles brought the northern United States and southern Canada to a standstill, leaving many people cold and dark for days or even weeks. Whether it’s wind turbines, electric towers, drones or aircraft wings, de-icing often relies on methods that are time-consuming, expensive and/or use a lot of energy and a variety of chemicals. But looking at nature, McGill’s researchers think they’ve found a promising new way to solve the problem. They were inspired by the wings of gentoo penguins swimming in the icy waters of Antarctica, and their fur doesn’t freeze even when the outside surface temperature is well below freezing.
We first investigated the properties of lotus leaves, which are very good at removing water, but it turned out that they are less effective at removing ice,” said Ann Kitzig, who has been looking for solutions for almost a decade and is an assistant professor. Doctor of Chemical Engineering at McGill University, Director of the Laboratory for Biomimetic Surface Engineering: “It wasn’t until we began to investigate the properties of penguin feathers that we discovered a naturally occurring material that simultaneously sheds water and ice. ”
The image on the left shows the microstructure of a penguin feather (a close-up of a 10 micron insert corresponds to 1/10 of the width of a human hair to give a sense of scale). These barbs and twigs are the central stems of the branching feathers. . “Hooks” are used to join individual feather hairs together to form a cushion. On the right is a stainless steel wire cloth that the researchers decorated with nanogrooves, reproducing the hierarchy of penguin feather structures (wire with nanogrooves on top).
“We found that the hierarchical arrangement of the feathers themselves provides water-releasing properties, and their serrated surface reduces ice adhesion,” explains Michael Wood, a recent graduate student working with Kitzig and one of the co-authors of the study. New article in ACS Applied Material Interfaces. “We were able to replicate these combined effects with laser-cut woven wire mesh.”
Kitzig added: “It may seem counterintuitive, but the key to separating the ice is all the pores in the mesh that absorb water under freezing conditions. The water in those pores eventually freezes, and as it expands, it creates cracks, just like you would be in refrigerator. It’s the same as seen in the ice cube tray. We need very little effort to remove the ice from our mesh because the cracks in each of these holes tend to meander along the surface of these braided wires.”
The researchers tested the stenciled surface in a wind tunnel and found that the treatment was 95% better at resisting icing than unwrapped polished stainless steel sheets. Since no chemical treatment is required, the new method offers a potentially maintenance-free solution to the problem of ice formation on wind turbines, towers, power lines and drones.
“Given the number of passenger aviation regulations and the associated risks, it is unlikely that aircraft wings will simply be wrapped in metal mesh,” Kitzig added. “It is possible, however, that one day the surface of an aircraft wing may have the texture that we are studying, and since traditional de-icing methods work together on the wing surface, de-icing will occur by fusing penguin wings. inspired by the texture of the surface.”
“Reliable anti-icing surfaces based on dual functionality – microstructure-induced ice flaking with nanostructure-enhanced water repellency overlay”, Michael J. Wood, Gregory Brock, Juliette Debre, Philippe Servio and Anne-Marie Kitzig in ACS Appl. alma mater.interface
McGill University, founded in 1821 in Montreal, Quebec, is the number one university in Canada. McGill University is consistently ranked among the top universities both nationally and internationally. It is a world-renowned institution of higher education with research activities spanning three campuses, 11 colleges, 13 professional colleges, 300 study programs and over 40,000 students, including over 10,200 graduate students. McGill attracts students from over 150 countries, and its 12,800 international students make up 31% of the student body. More than half of McGill students say their first language is not English, and about 19% of them speak French as their first language.