Multi-level micro-/nanostructures of butterfly wings adapt at low temperature to water repellency

We show that micro-/nanostructure effects achieve water repellency of Morpho nestira butterfly wings under low temperature and changeable relative humidity. It is found that the multi-level micro-/nanostructures on wing scales effectively retard low-temperature-induced wetting, and achieve water repellency, accompanied with low adhesion under environmental humidity conditions. The mechanism of the extended water repellency is elucidated based on the micro-/nanostructure effect that can be adapted to low temperature and relative humidity. This finding offers an insight into micro-/nanostructures of butterfly wings, which helps to design novel interface materials to be applied in anti-frosting, anti-fogging and anti-icing projects.