Wetting of hairy surfaces


Bernardino, N.1 and Dietrich, S.1

1 Max-Planck-Institut für Metallforschung, Stuttgart , Germany


The leaves of a Lady's Mantle are densely covered with hairs that display a rather surprising wetting behaviour: droplets of water can rest on the hairs, without contact with the leaf's surface, even though the hairs are hydrophilic [Otten & Herminghaus, Langmuir 20, 2405 (2004)]. It was suggested that this behaviour is due to an interplay of capillary interactions and the elasticity of the hairs. We put these arguments into a more quantitative framework to try to understand better the origin of this behaviour, and estimate the criteria for a furry hydrophilic surface to behave as effectively hydrophobic.