Mechanical models for the adhesive friction of nano- and micro-particles

Abstract

Friction is common in human’s daily life and production that may be either detrimental or beneficial. The friction law at microscale or even smaller scales nevertheless is lacking. In the present work, on the basis of JKR model for adhesive contact and by analogy with the emission of dislocations at a crack tip, the critical tangential force has been obtained for the onset of sliding. When the tangential force in adhesive contact induces a torque at the interface, a mechanical model for rolling adhesion has been presented on the basis of the assumption that it is governed by adhesion hysteresis. The critical torque and tangential force for rolling onset have been determined, which may be taken as measure for the rolling friction force. Comparisons with relevant experiments and models have been made to support the present concept. A kind of friction duality in small sized particles can thus be predicted.