Uni-, Bi-, and Tri-Directional
Wetting Caused by Nanostructures with Anisotropic Surface
Energies
- Publication date
- Publisher
Abstract
Wetting is a pervasive phenomenon that governs many natural
and
artificial processes. Asymmetric wetting along a single axis, in particular,
has generated considerable interest but has thus far been achieved
only by the creation of structural anisotropy. In this paper, we report
that such directional wetting can also be achieved by anisotropically
coating nanostructure surfaces with materials that modify the nanostructure
surface energy, a phenomenon that has not been observed in natural
or artificial systems thus far. Moreover, by combining this newfound
chemical influence on wetting with topographic features, we are able
to restrict wetting in one, two and three directions. A model that
explains these findings in terms of anisotropy of the pinning forces
at the triple phase contact line is presented. Through the resulting
insights, a flexible method for precise control of wetting is created