Electrotunable interfacial friction: A brief review

Using different external stimuli to control interfacial friction, rather than just pursuing low friction, is a highly attractive research regime due to its economic and scientific importance. One option to achieve such a goal is to use external stimuli that modulate the energy dissipation pathways. In particular, electric stimuli such as surface potential has gained remarkable interest for two reasons: Electrotunable friction has the potential for real-time, in situ manipulation of friction, and external electric stimuli is relatively easy to apply and to remove for reversible change. In this review, we explore the emerging research area of electrotunable friction mainly under the boundary lubrication situation, when the contacting surfaces are separated by a molecularly thin layer, reviewing typical achievements from experiments using electrochemical atomic force microscopy and modified surface force balances, as well as molecular dynamics simulations. Additionally, we explore the theoretical and practical challenges that may need to be tackled in the future.