Atomic force microscope manipulation of multiwalled and single walled carbon nanotubes with reflux and ultrasonic treatments

We are reporting the atomic force microscope (AFM) nanomanipulation of ultrasonically dispersed and reflux-oxidized multiwalled carbon nanotubes (MWCNT) and single walled carbon nanotubes (SWCNT) by controlling the AFM tip with a NanoManipulator on a silicon substrate. The structure and the morphology of the carbon nanotubes (CNT) were confirmed with AFM interfaced with NanoManipulator and transmission electron microscope. The modifying parameter, which controls the force exerted by AFM tip, was set to be 0.5 nA in each case (0.5 nA = 20 nN). Bending was observed in ultrasonically dispersed MWCNTs, whereas, cutting was observed for reflux-oxidized MWCNTs along with the lateral movements. Similar observations were found for SWCNTs with sharp cuts and lateral displacements. The results show that CNTs deform by combining bending and distortion when subjected to large mechanical forces exerted by the tip of the AFM. The magnitude of the force, required to deform the reflux-oxidized CNTs is less than that for the ultrasonically dispersed CNTs, for both MWCNTs and SWCNTs.