Characterization of nanofriction of MoS2 and WS2 nanotubes

MoS2 and WS2 nano-objects have been studied in tribological applications and increasingly in other applications where nano-objects come into sliding contact with each other. Fundamental friction studies on a single nano-object are of interest. In this research atomic force/friction force microscopy (AFM/FFM) studies have been conducted on MoS2 and WS2 nanotubes to study scale effects and analyze the contributions of surface topography and orientation effects on friction. Variations in friction force due to topography were determined to be as a result of the ratchet mechanism and "collision" effect. There were no orientation effects on coefficient of friction on either of the nanotubes. (C) 2014 Elsevier B.V. All rights reserved.