title: Superhydrophobicity and superhydrophilicity of regular nanopatterns.
abstract: The hydrophilicity, hydrophobicity, and sliding behavior of water droplets on nanoasperities of controlled dimensions were investigated experimentally. We show that the "hemi-wicking" theory for hydrophilic SiO(2) samples successfully predicts the experimental advancing angles and that the same patterns, after silanization, become superhydrophobic in agreement with the Cassie-Baxter and Wenzel theories. Our model topographies have the same dimensional scale of some naturally occurring structures that exhibit similar wetting properties. Our results confirm that a forest of hydrophilic/hydrophobic slender pillars is the most effective superwettable/water-repellent configuration. It is shown that the shape and curvature of the edges of the asperities play an important role in determining the advancing angles.
authors.affiliation: Centre for Cell Engineering, IBLS, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K.
authors.forename: Elena
authors.initials: E
authors.lastname: Martines
authors.forename: Kris
authors.initials: K
authors.lastname: Seunarine
authors.forename: Hywel
authors.initials: H
authors.lastname: Morgan
authors.forename: Nikolaj
authors.initials: N
authors.lastname: Gadegaard
authors.forename: Chris D W
authors.initials: CD
authors.lastname: Wilkinson
authors.forename: Mathis O
authors.initials: MO
authors.lastname: Riehle