Wing ice poses a great threat to aircraft flight safety, but inspired by mint leaves, scientists at Northwestern University have successfully developed a new anti-ice coating. The team said they took this inspiration by looking at frost patterns on certain types of plant leaves.
Mint leaves (pictured: Northwestern University)
Researchers at the school’s School of Engineering say the mint leaves have tiny peaks and valleys that exhibit ripple-like geometry, making it impossible for frost to be evenly distributed across the entire surface of the leaves.
This new surface coating, inspired by this, reduces frost formation by up to 60%. Kyoo-Chul Park says this phenomenon has been noticed for thousands of years, but no one has been able to explain how it was formed.
Through computer simulations and experiments, Park conducted further research with team members and found that while condensation accumulates well at the peak of the mint leaf, the bottom is rare.
Even below freezing points, where extreme frost evaporates quickly, it provides guidance for developing new antifreeze surface coatings.
Maple leaf-based coating effect demonstration (photo: Northwestern University)
In subsequent experiments, Park achieved the best design to mimic this natural phenomenon, creating a set of tiny peaks only 1mm high with a 40-60-degree downward inclination in the middle.
The results show that although the peak does have a thin layer of frost, the unique surface shape still greatly enhances the effect of defrosting.
“Frost-free areas can initiate defrosting processes, saving materials and energy for frost problems,” says Park. All we have to do is provide others with a pattern design for this jagged surface.”
Details of the study have been published in the recent lys in the Proceedings of the National Academy of Sciences (PNAS). Originally published as Frost-free zone on macrotextured Surfaces.