Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: POSTERS Micro- and Nanofluidics
CPP 38.14: Poster
Thursday, March 26, 2009, 17:00–19:30, P3
Small droplets on superhydrophobic substrates — •Markus Gross1,2, Fathollah Varnik1,2, and Dierk Raabe1 — 1Max-Planck Institut für Eisenforschung, Düsseldorf, Germany — 2Interdisciplinary Center for Advanced Materials Simulation, Ruhr-Universität Bochum, Germany
We investigate the stability of liquid droplets on a regular superhydrophobic substrate for the case of droplets that are of comparable size to the surface asperities.
A simple analytic three-dimensional free energy model is proposed and compared to the results obtained from lattice Boltzmann computer simulations. Both approaches are found to be in good agreement. The stability of the fakir state is shown to depend on the substrate geometry, contact angle and droplet size. Remarkably, we are able to observe a new metastable state of partial impalement that is different from the fakir or Wenzel state. We find that, due to this new state, an evaporating droplet can be saved from going over to the Wenzel state and instead remains close to the top of the surface texture.