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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: SYMPOSIUM Driven Soft Matter IV
CPP 19.4: Vortrag
Mittwoch, 27. Februar 2008, 14:45–15:00, C 130
Fluid interfaces under shear: Studying the Ising model under drive. — Tom Smith1, Oleg Vasilyev2, Douglas B. Abraham3, •Anna Maciolek2, and Matthias Schmidt1 — 1H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK — 2Max-Planck-Institut fuer Metallforschung, Heisenbergstr. 3, D-70569 Stuttgart, Germany — 3Theoretical Physics, Department of Physics, University of Oxford
We use a phase-separated driven two-dimensional Ising lattice gas in order to model liquid-liquid interfaces exposed to shear flow parallel to the interface. The model is confined between two parallel walls and two different types of external field with direction parallel to the walls are used to drive the system out-of-equilibrium : i) the field acts locally at the walls, or ii) the field varies linearly with distance across the slit. From computer simulations using Kawasaki (conserved order parameter) dynamics we obtain structural information such as the lateral and transversal correlation lengths at the interface. In equilibrium the confinement of the interface due to the presence of walls reduces its width and the characteristic transverse (correlation) length, while increasing the interfacial free energy. We find that shear induces similar effects. Furthermore we test whether the roughness of the driven interface decreases as compared to the equilibrium case. The global effects of shear on the system are in particular surprising for case i) where only particles at the boundaries of the system are driven. The relationship of our findings to recent experimental results in sheared phase-separated colloidal dispersions is discussed.