title: Wetting and self-cleaning properties of artificial superhydrophobic surfaces.
abstract: The wetting and the self-cleaning properties (the latter is often called the "Lotus-Effect") of three types of superhydrophobic surfaces have been investigated: silicon wafer specimens with different regular arrays of spikes hydrophobized by chemical treatment, replicates of water-repellent leaves of plants, and commercially available metal foils which were additionally hydrophobized by means of a fluorinated agent. Water droplets rolled off easily from those silicon samples which had a microstructure consisting of rather slender spikes with narrow pitches. Such samples could be cleaned almost completely from artificial particulate contaminations by a fog consisting of water droplets (diameter range, 8-20 microm). Some metal foils and some replicates had two levels of roughening. Because of this, a complete removal of all particles was not possible using artificial fog. However, water drops with some amount of kinetic impact energy were able to clean these surfaces perfectly. A substrate where pronounced structures in the range below 5 microm were lacking could not be cleaned by means of fog because this treatment resulted in a continuous water film on the samples.
authors.affiliation: Nees-Institut für Biodiversität der Pflanzen, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 170, D-53115 Bonn, Germany. r.fuerstner@stoeu.com
authors.forename: Reiner
authors.initials: R
authors.lastname: Fürstner
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Barthlott
authors.forename: Christoph
authors.initials: C
authors.lastname: Neinhuis
authors.forename: Peter
authors.initials: P
authors.lastname: Walzel