Smooth surfaces freeze faster (Image: Lehtikuva OY/Rex Features)

AS TEMPERATURES plummet, lotus leaves can remain surprisingly free of frost. Their secret, which turns out to be related to their water-repelling properties, could be applied to building frost-repelling materials.

Water droplets roll off lotus leaves partly because of the roughness of their surface on the nanoscale. The irregularities trap air beneath any water droplets on the surface, preventing them from making contact. Artificial surfaces with similar properties are equally water-repellent, and also resist frost formation.

Now Yanlin Song and his team at the Chinese Academy of Sciences, Beijing, have shown …