Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: Friction and Rheology
CPP 30.3: Vortrag
Dienstag, 13. März 2018, 12:30–12:45, C 264
The transition from hydrodynamic via interfacial to dry friction for sheared surfaces in water — •Alexander Schlaich1,2, Julian Kappler1, and Roland R. Netz1 — 1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 2Laboratoire Interdisciplinaire de Physique (LIPhy), CNRS and Université Grenoble Alpes, F-38000 Grenoble, France
The friction force between hydrated surfaces under shear is important in various fields ranging from biolubrication to flocculation and jamming. For large surface separation friction is well described by hydrodynamics and dominated by the water viscosity. As the normal pressure increases the surface separation goes down, leading to water properties that differ drastically from bulk and where the interfacial viscous properties dominate, thus modifying the friction force. When the normal pressure is so high that all water is squeezed out, dry friction is obtained.
We establish the general framework that describes the separation-dependent crossover between these three regimes. We concentrate on neutral yet polar membrane-like surfaces which exhibit stable water films and are governed by strong hydration repulsion and report extensive atomistic non-equilibrium molecular dynamics simulations. In that case it is important to correctly account for the constant water chemical potential as the water number changes according to the applied normal pressure.