NER: Nanoscale Profiling of the Elastic and Viscoelastic Response of Individual Nanotubes

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TITLE: Nanoscale Profiling of the Elastic and Viscoelastic Response ofIndividual Carbon NanotubesAbstract: The goal of the proposed activity is the quantitative, nanoscale profiling of local variations in the elastic and viscoelastic properties of multiwall nanotubes (MWNTs). Ultrasonic force microscopy (UFM) and heterodyne force microscopy (HFM) will be utilized for the quantitative extraction and mapping of the reduced Young's modulus and loss factor, respectively, along the axis of single tubes grown via arc-discharge or chemical vapor deposition. Modulus extraction will exploit the nonlinear interaction between a scanning probe tip and the nanotube surface at ultrasonic vibrations ( 10 MHz) to determine the MWNT contact stiffness within a small (10nm x 10nm) area along the axis. The viscoelastic imaging will utilize a heterodyne approach wherein ultrasonic vibrations are applied to both the MWNT and the nanoprobe tip to produce a time-resolved mechanical phase image for the MWNT viscoelastic response. Thermal studies (100K to 600K) will also be undertaken for HFM nanotube profiling to investigate the thermal evolution of visoelasticity.