8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Thu 811:10-14:00P7.79Viscous dissipation in confined liquid filmsFrieder Mugele, 1 Sissi de Beer, 1 Wouter K. den Otter, 1 Dirk van den Ende, 1 andWim Briels 11 Univ. Twente - MESA+ institute, Physics of Complex Fluids, PO Box 217 7500 AE,Enschede, NetherlandsWe present Atomic Force Microscopy measurements as well as equilibrium molecular dynamics(MD) simulations of conservative and dissipative forces in simple Lennard-Jones like confinedliquids. Both conservative and dissipative forces are shown to display an oscillatory behavior. Localpeaks of excess dissipation occur for film thicknesses with a non-integer number of molecularlayers. The dissipation peaks, which we extract from the decay of the time autocorrelation of theforce fluctuations, correlate with variations of the film structure between well-organized hexagonallayers and more disordered layers with cubic symmetry.79