The kinetic friction between a nanowire and a flat substrate measured using nanomanipulation with optical microscopy

Abstract

The kinetic frictional force between a nanowire and its supporting flat substrate was measured using nanomanipulation with optical microscopy at ambient atmosphere. During testing, the nanowire was pushed at its center point by a sharp tip and thus exhibited an arc shape held by the frictional shear stress (kinetic friction per area). The arc-shaped nanowire slid along the supporting substrate with further pushing. The frictional shear stress was derived from the arc shape of the nanowire based on the theory of elasticity. The frictional shear stresses of Al2O3 nanowires on the Si and SiN substrates were measured to be 2.0 ± 0.2 and 1.5 ± 0.2 MPa, respectively. It was found that the lengths of the nanowires and their angular orientations with the substrate, the arc shapes being formed and the driving mode of the tip had insignificant effects on the measured frictional shear stress.