Effect of adhesion on dynamic and static friction in surface micromachining

We measure friction of monolayer-lubricated microelectromechanical systems surfaces under both static and dynamic conditions while continuously controlling the applied normal load at positive or negative values (i.e., compression or tension). The dynamic friction experiment methodology we have devised enables fitting to the complete one-dimensional equation of motion. We observe friction at zero applied load, and quantitatively attribute this to interfacial adhesion. Within error, the adhesive force is the same under static and dynamic conditions. (C) 2004 American Institute of Physics.