Georgia Institute of TechnologypicoForce Laboratory
Zinc Oxide nanobeltProfile: Elisa RiedoNanofriction plot

Atomistic Origin of Friction Forces

    The fundamental understanding of friction and adhesion forces between dry and lubricated surfaces is crucial in fields as widespread as earthquake dynamics and human joints. From a technological point of view, with the miniaturization of moving components in many technological devices, such as micro and nano-electromechanical systems (MEMS) and magnetic hard disk drives, it has become of primary importance to study surface forces like friction, viscous drag and adhesion at micro and nanoscale. Despite to its scientific and technological importance, there are still no generally accepted explanations for the basic laws of friction and for the origin of diverse adhesion forces.

    Our goal is to understand the atomic origin of friction, adhesion and their relationship with phenomena such as wetting, gas-liquid phase transitions under nanoconfinement, etc.

    In particular, we are studying thermally activated phenomena in nanoscopic sliding friction by means of atomic force microscope (AFM) measurements of the temperature and velocity dependence of sliding friction. These phenomena can be water capillary condensation in the interstitials between the sliding bodies or tip hopping on the surface interaction potential. Being related to the probability of transition between different equilibrium configurations, thermal activation is more efficient at low AFM tip velocities, i.e. for longer contact time there are higher probabilities to activate the process (condensation or hopping).


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