Regensburg 2010 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 26: Micro and Nanofluidics I
CPP 26.8: Talk
Wednesday, March 24, 2010, 16:00–16:15, H39
Reduced Interfacial Entanglement Density Affects Boundary Condition of Polymer Flow — Oliver Bäumchen1, •Matthias Lessel1, Renate Fetzer1,2, and Karin Jacobs1 — 1Saarland University, Experimental Physics, D-66041 Saarbrücken, Germany — 2Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
Hydrodynamic boundary conditions play a crucial role in the flow dynamics of thin films [1] and can be probed by the analysis of liquid front profiles [2]. For long-chained polymer films it was reported that a deviation from a symmetric profile is a result of viscoelastic effects. In this study [3], however, evidence is given that merely a slip boundary condition at the solid/liquid interface can lead to an asymmetric profile. Variation of molecular weight shows that slippage is directly linked to chain entanglements. We find a reduced entanglement density at the solid/liquid interface (factor 3 to 4), which stresses the importance of considering non-bulk polymer properties in the vicinity of an interface.
[1] O. Bäumchen et al., J.Phys.: Condens. Matter 21 (2009, in press).
[2] O. Bäumchen et al., in IUTAM Symposium on Advances in Micro- and Nanofluidics, edited by M. Ellero, X. Hu, J. Fröhlich, N. Adams (Springer, 2009).
[3] O. Bäumchen et al., Phys. Rev. Lett. (2009, in press).