Berlin 2015 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 38: Wetting, Micro and Nanofluidics (joint session CPP/ DY)

DY 38.2: Talk

Wednesday, March 18, 2015, 15:15–15:30, C 243

Drying and Wetting transitions on irregular rough substrates. — •Segun Gideon Ayodele, Ciro Semprebon, Renaud Dufour, Stephan Herminghaus, and Martin Brinkmann — Max-Planck Institut für Dynamik und selbstorganisation, 37077 Göttingen.

Drying and wetting transitions on non-flat solids of homogeneous wettability are studied employing a sharp interface model. Interfacial configurations in the Grand canonical ensemble and corresponding numerical energy minimizations for a non-zero microscopic contact angle are compared to predictions based on the statistical model proposed in Refs. [1,2]. This mean field model considers exclusively local descriptors of the substrate topography such as the distribution of heights, as well as averages of the slope and its square at a given height. In contrast to the continuous desorption isotherm of a zero microscopic contact angle, we observe an increasingly discontinuous decay of the average film thickness in our numerical simulations during a desorption as the microscopic contact angle is increased. The pressure of the final drying transition as observed in the simulated annealing and numerical energy minimization is in agreement with predictions of the `Wenzel prewetting' transition in the mean field model [1,2].

1. S. Herminghaus, Eur. Phys. J. E 35, 43 (2012).

2. S. Herminghaus, Phys. Rev. Lett., 109,236102 (2012).