Berlin 2015 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 15: Statistical Physics - general
DY 15.10: Talk
Tuesday, March 17, 2015, 12:00–12:15, BH-N 334
Electrical charging effects on sliding lubrication properties of a model confined ionic liquid — •Rosario Capozza1, Andrea Benassi2, Andrea Vanossi3,1, and Erio Tosatti1,4 — 1International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy — 2Empa, Materials Science and Technology, Uberlandstrasse 129, 8600 Dubendorf, Switzerland — 3CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste, Italy — 4International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34014 Trieste, Italy
Ionic liquids lubricants, used under conditions of nanometric confinement between parallel plates or tip-surface gaps, explore the dependence of friction upon charging, suggestive of some electrical control of friction. Using a simple ionic liquid model, we first study by molecular dynamics the friction between parallel plates under conditions of successive layering reached by squeezout under an increasing inter-plate force. We then simulate the frictional changes brought about by different charging states of the plates, related to charging-induced switches corresponding to squeezout (or suck-in) transitions between different layering states as predicted by local minima in the charge-dependent enthalpy curves. Although the actual frictional behavior obtained does depend upon the assumed features and parameters of the model liquid and its interaction with the plates, the broader scenario obtained for charging effects, its relationship to the equilibrium layering and its enthalpy characterization appear of general value.