Nanotribological behavior of a single silver nanowire on graphite

The nanotribological characteristics of silver nanowires (Ag NWs) are of great importance for the reliability of their applications in flexible nanodevices involving mechanical interactions. The frictional behaviors of Ag NWs on graphite substrate were directly investigated by atomic force microscopy (AFM) nanomanipulation. The relatively short NWs demonstrate three forms of motion-rotation, translation and a combination of the two-whose frictional behaviors behave like rigid rods. The relatively long Ag NW shows characteristics of a flexible beam, whose friction increases with an increase in the bending angle of the NW. The friction between the NW and substrate increases linearly with an increase in the length of the NW. The long Ag NW displays extraordinary flexibility that can be folded to different shapes, and the friction of the folded NW becomes smaller due to the decreased bending deformation. The critical aspect ratio of the Ag NW on graphite substrate for two different frictional behaviors between the relatively long and short NWs is found to be 12-15. These findings can deepen the understanding of the frictional characteristics of Ag NWs and contribute to their quantitative interface design.