Regensburg 2016 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 46: Poster: Wetting, Nano- and Microfluidics

DY 46.1: Poster

Wednesday, March 9, 2016, 18:15–21:00, Poster B2

Theoretical study of slip effects on a dewetting drop — •Tak Shing Chan¹, Joshua D. McGraw^1,2, Thomas Salez³, and Martin Brinkmann¹ — ¹Experimental Physics, Saarland University, D-66041, Saarbrücken, Germany — ²Département de Physique, Ecole Normale Supérieure / PSL Research University, CNRS, 24 rue Lhomond, 75005 Paris, France — ³PCT Lab, UMR Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris, France

A recent experimental study on the dewetting of polymer microdroplets have shown that slip plays a dominating role on the shape evolution and the motion of the contact line (Under review). Particularly, a transient bump is observed for relatively small slip lengths, while a bump is avoided for larger values. In this theoretical study, we investigate the dewetting of a drop in a wider regime of parameter space. Using the boundary element method, we solve for the axisymmetric Stokes flow with i) the Navier-slip boundary condition at the solid/liquid boundary, and ii) a time-independent microscopic contact angle at the contact line position. We compute the profile evolution for different slip lengths and equilibrium contact angles. We find that when decreasing the slip length, the characteristic size of the bump first increases, and then decreases. More interestingly, the size of the bump even reaches zero, meaning no bump is observed, if the slip length is small enough. This remarkable result may indicate a crossover to the quasi-static regime when the slip length is very small.