Superhydrophobic Structures on the Basis of Aspen Leaf Design

This study is concerned with an analysis of the structural and mechanical design concepts in naturally occurring superhydrophobic structures. It is shown that the non-wetting behaviour of the leaves of two members of the aspen family can be primarily attributed to a dual-scale surface structure consisting of micro-papillae and nano-wax platelets. However, the non-wetting effect is further enhanced by the large leafstalk aspect ratio and associated low moment of inertia, offering little resistance to leaf bending. These leafstalk dimensions result in excessive shaking of the leaves even when there is no noticeable breeze, promoting efficient water droplet roll-off and dry leaf surfaces. It is tentatively concluded that this leaf design may contribute to the aspens' ability to quickly grow in a wide range of environmental conditions. Mimicking the combined effects of micro/nanostructure surface morphology and mechanical motion could be useful in developing a broader design concept range for superhydrophobic...