Regensburg 2013 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 34: Poster: Wetting, Micro and Nano Fluidics
CPP 34.3: Poster
Wednesday, March 13, 2013, 16:30–18:30, Poster C
Faster than spinodal dewetting: Ultra-thin liquid polystyrene films on silanized Si wafers — •Matthias Lessel1, Oliver Bäumchen2, Markus Rauscher3, and Karin Jacobs1 — 1Department of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany — 2Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada L8S 4M1 — 3Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
In recent years, many studies showed that a thin liquid film on a solid surface in air bears more complexity than expected from a simple three-layer-system: e.g. a highly mobile surface layer in case the liquid is an unentangled polystyrene (PS) melt (Yang et al., Science 2010; Seemann et al., J. of Polym. Sci. 2006) or a nearly full slip boundary condition for the PS melt on a solid substrate (Bäumchen et al., PRL 2009). Our study focuses on such phenomena and explores their influence on dewetting. We use hydrophilic and -phobic Si wafers, either covered by a highly ordered silane self-assembeld monolayer or by a thin layer of an amorphous fluoropolymer. On each of the substrates, one expects for a certain set of parameters spinodal dewetting for the PS melt (Seemann et al., PRL 2001). However, contrary to expectations, we observed a thermally activated nucleation process of hole formation instead of spinodal dewetting. The observed behavior is similar to results on free standing polymer films (Croll et al., Macromolecules 2012). A theory based on the capillary model of Croll et al. taking the effective interface potential into account will be presented to describe the results.