Slip-controlled thin-film dynamicsR. Fetzer1, M. Rauscher2, 3, A. Münch4, 5, B. A. Wagner5 and K. Jacobs1
1 Department of Experimental Physics, Saarland University 66123 Saarbrücken, Germany
2 Max-Planck-Institut für Metallforschung - Heisenbergstr. 3 70569 Stuttgart, Germany
3 ITAP, University of Stuttgart - Pfaffenwaldring 57, 70569 Stuttgart, Germany
4 Institute of Mathematics, Humboldt University Berlin - 10099 Berlin, Germany
5 Weierstrass Institute for Applied Analysis and Stochastics Mohrenstr. 39, 10117 Berlin, Germany
received 13 March 2006; accepted in final form 4 July 2006
published online 19 July 2006
In this study, we present a novel method to assess the slip length and the viscosity of thin films of highly viscous Newtonian liquids. We quantitatively analyse dewetting fronts of low-molecular-weight polystyrene melts on octadecyl- (OTS) and dodecyltrichlorosilane (DTS) polymer brushes. Using a thin-film (lubrication) model derived in the limit of large slip lengths, we can extract slip length and viscosity. We study polymer films with thicknesses between 50 and 230 and various temperatures above the glass transition. We find slip lengths from 100 up to 1 on OTS- and between 300 and 10 on DTS-covered silicon wafers. The slip length decreases with temperature. The obtained values for the viscosity are consistent with independent measurements.
83.80.Sg - Polymer melts.
47.15.gm - Thin film flows.
83.50.Lh - Slip boundary effects (interfacial and free surface flows).
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