Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: POSTERS Micro- and Nanofluidics
CPP 38.8: Poster
Donnerstag, 26. März 2009, 17:00–19:30, P3
Dewetting of thin liquid films on viscoelastic substrates — •Konstantina Kostourou1, Dirk Peschka3, Andreas Münch2, Barbara Wagner3, Stephan Herminghaus1, and Ralf Seemann1,4 — 1Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany — 2School of Mathematical Sciences, University of Nottingham, UK — 3Weierstrass Institute for Applied Analysis and Stochastics, Berlin, Germany — 4Experimental Physics, Saarland University, Germany
We study the dewetting of thin polymer films on viscoelastic (PDMS and molten PMMA) substrates. Experimentally we observe that the dewetting rates increase as we increase the substrate elasticity, whereas they show a two-phase behavior as we tune the substrate viscosity. Furthermore, we find that characteristic rim shapes and substrate deformations depend on the viscoelasticity of the underlying substrate. In our theoretical approach we couple the Navier-Stokes equations to a Kelvin-Voigt model to describe the liquid and solid phase respectively. We derive a set of one-dimensional thin-film equations for the liquid film and the solid substrate, where the depth averaged velocity of the liquid and the deformation of the solid substrate is largely tangential to the liquid-solid interface. Finally, we compare the experimental results with the predictions of our model. Whereas we observe a deviation in the case of the PDMS substrates, we find them to be in good agreement in the case of the PMMA substrates. Specifically, our model is able to define both the dewetting dynamics of our system and the deformation of the substrate close to the three phase contact line.