International. A team of scientists from Duke University in the United States and James Cook University in Australia have discovered how red-eyed insects keep their wings clean and free of contaminants.
Scientists say the secret is that falling water droplets melt and then jump off the wings of flying insects, a phenomenon they call self-propelled dew drops. The new discovery would allow the development of new self-cleaning coatings.
"Traditionally, it was thought that cleaning natural surfaces takes place mainly by the so-called 'lotus effect'. In this effect, first observed in the lotus leaf, "rainwater droplets roll along the leaf and wash dirt from the surface, just like water droplets on the hood of a freshly waxed car," said Dr. Jolanta Watson of James Cook University.
However, the team says Mother Nature uses other ways to clean surfaces, especially in areas where rain doesn't fall for long periods of time. The findings are "fundamentally different from the conventional wisdom involving the filming or shocking of droplets on superhydrophobic surfaces," according to the scientists.
When the cicada's wings are exposed to water vapor, the dew forms small droplets that spontaneously melt together and are self-propelled off the surface by changes in surface energy. The jump is automatic, and the droplets can rid the superhydrophobic surface of dirt and other contaminants.
