Water droplet motion control on superhydrophobic surfaces: Exploiting the Wenzel-to-Cassie transition

Guangming Liu, Lan Fu, Andrei V. Rode, Vincent S.J. Craig

    Research output: Contribution to journalArticlepeer-review

    127 Citations (Scopus)

    Abstract

    Water droplets on rough hydrophobic surfaces are known to exist in two states; one in which the droplet is impaled on the surface asperities (Wenzel state) and the other, a superhydrophobic state in which air remains trapped beneath the droplet (Cassie state). Here, we demonstrate that water droplets can transit from the Wenzel-to-Cassie state even though the former is energetically favored. We find that two distinct superhydrophobic states are produced. One is a true Cassie state, whereas the other exhibits superhydrophobicity in the absence of a vapor phase being trapped in the surface roughness. Furthermore, we can selectively drive the motion of water droplets on tilted structured hydrophobic surfaces by exploiting Wenzel-to-Cassie transitions. This can be achieved by heating the substrate or by directly heating the droplet using a laser.

    Original languageEnglish
    Pages (from-to)2595-2600
    Number of pages6
    JournalLangmuir
    Volume27
    Issue number6
    DOIs
    Publication statusPublished - 15 Mar 2011

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