Dissemin is shutting down on January 1st, 2025

Published in

Elsevier, Advances in Colloid and Interface Science, (222), p. 104-109, 2015

DOI: 10.1016/j.cis.2014.06.002

Links

Tools

Export citation

Search in Google Scholar

Super liquid-repellent layers: The smaller the better

Journal article published in 2014 by Hans-Jürgen Butt ORCID, Doris Vollmer, Periklis Papadopoulos
This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

Full text: Download

Green circle
Preprint: archiving allowed
Red circle
Postprint: archiving forbidden
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

Super liquid-repellent layers need to have a high impalement pressure and high contact angles, in particular a high apparent receding contact angle. Here, we demonstrate that to achieve both, the features constituting the layer should be as small as possible. Therefore, two models for super liquid-repellent layers are theoretically analyzed: A superhydrophobic layer consisting of an array of cylindrical micropillars and a superamphiphobic layer of an array of pillars of spheres. For the cylindrical micropillars a simple expression for the apparent receding contact angle is derived. It is based on a force balance rather than a thermodynamic approach. The model is supported by confocal microscope images of a water drop on an array of hydrophobic cylindrical pillars. The ratio of the width of a pillar w to the center-to-center spacing a is a primary factor in controlling the receding angle. Keeping the ratio w/a constant, the absolute size of surface features should be as small as possible, to maximize the impalement pressure.