Strain energy and lateral friction force distributions of carbon nanotubes manipulated intoshapes by atomic force microscopy

Abstract

The interplay between local mechanical strain energy and lateral frictional forcesdetermines the shape of carbon nanotubes on substrates. In turn, because of itsnanometer-size diameter, the shape of a carbon nanotube strongly influences its localelectronic, chemical, and mechanical properties. Few, if any, methods exist for resolving thestrain energy and static frictional forces along the length of a deformed nanotubesupported on a substrate. We present a method using nonlinear elastic rod theory in whichwe compute the flexural strain energy and static frictional forces along the length of singlewalled carbon nanotubes (SWCNTs) manipulated into various shapes on a cleanSiO2 substrate. Using only high resolution atomic force microscopy images of curved singlewalled nanotubes, we estimate flexural strain energy distributions on the order ofattojoules per nanometer and the static frictional forces between a SWCNT andSiO2 surface to be aminimum of 230 pN nm−1.