Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 22: SYMPOSIUM Microfluidics II: Soft objects in flow, open geometries
CPP 22.9: Vortrag
Donnerstag, 30. März 2006, 16:45–17:00, ZEU 160
Pearling instability of nanoscale fluid flow confined to a chemical channel — •M. Rauscher1,2, J. Koplik3, T. S. Lo3, and S. Dietrich1,2 — 1Max-Planck Institut für Metallforschung, Heisenbergstr. 3, 70569 Stuttgart, Germany — 2Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany — 3Benjamin Levich Institute and Department of Physics, City College of the City University of New York, New York, NY 10031, USA
We investigate the flow of a nano-scale incompressible ridge of low-volatility liquid along a No-dqchemical channelNo-dq: a long, straight, and completely wetting stripe embedded in a planar substrate, and sandwiched between two extended less wetting solid regions. Molecular dynamics simulations, a simple long-wavelength approximation, and a full stability analysis based on the Stokes equations are used, and give qualitatively consistent results. While thin liquid ridges are stable both statically and during flow, a (linear) pearling instability develops if the thickness of the ridge exceeds half of the width of the channel. In the flowing case periodic bulges propagate along the channel and subsequently merge due to nonlinear effects. However, the ridge does not break up even when the flow is unstable, and the qualitative behavior is unchanged even when the fluid can spill over onto a partially wetting exterior solid region.