Interfacial Friction Control

This review outlines the up‐to‐date research progress on controllable interfacial friction on both solid/solid and solid/liquid surfaces. Environment‐sensitive materials at a frictional interface react to certain external stimuli and provoke changes in surface chemistry, interfacial charge, and/or topography, which then cause a change in the coefficient of friction. The external stimuli might be solvent, electrolyte, pH, temperature, light, electric potential, and magnetic field etc. In a similar way, controllable fluid–solid friction (i.e., boundary slippage versus non‐slippage) can also be achieved by reversibly generating a gas lubricating layer at the interface or by changing the fluid–solid adhesion via physicochemical methods. The author comments are presented and outlooks proposed.