Issue 36, 2018

Wetting of soft superhydrophobic micropillar arrays


Superhydrophobic surfaces are usually assumed to be rigid so that liquids do not deform them. Here we analyze how the relation between microstructure and wetting changes when the surface is flexible. Therefore we deposited liquid drops on arrays of flexible micropillars. We imaged the drop's surface and the bending of micropillars with confocal microscopy and analyzed the deflection of micropillars while the contact line advanced and receded. The deflection is directly proportional to the horizontal component of the capillary force acting on that particular micropillar. In the Cassie or “fakir” state, drops advance by touching down on the next top faces of micropillars, much like on rigid arrays. In contrast, on the receding side the micropillars deform. The main force hindering the slide of a drop is due to pinning at the receding side, while the force on the advancing side is negligible. In the Wenzel state, micropillars were deflected in both receding and advancing states.

Graphical abstract: Wetting of soft superhydrophobic micropillar arrays

Supplementary files

Article information

Article type
29 Jun 2018
24 Aug 2018
First published
05 Sep 2018
This article is Open Access
Creative Commons BY license

Soft Matter, 2018,14, 7429-7434

Wetting of soft superhydrophobic micropillar arrays

P. Papadopoulos, B. Pinchasik, M. Tress, D. Vollmer, M. Kappl and H. Butt, Soft Matter, 2018, 14, 7429 DOI: 10.1039/C8SM01333K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity