Frictional and Electrical Properties of Multiwalled Carbon Nanotubes

This presentation examines the tribological properties and contact resistance of oriented capped carbon multiwalled nanotube (MWNT) films. Highly anisotropic tribological behavior of MWNT films oriented in mutually orthogonal directions is observed. The average values of coefficient of friction varied from high values (μ = 0.795) for vertically aligned nanotubes grown on rigid substrates to low values (μ = 0.090) for the same nanotubes dispersed flat on the same substrates. The results were insensitive to humidity, which is in contrast to graphite materials. The multiwalled nanotube layers also had a monotonic decrease in friction coefficient with increased surface temperature in both orientations, having a 32% drop in friction coefficient over a 73°C temperature rise. Preliminary results from contact resistance measurements of nanotube films grown through a porous alumina are investigated as a function of applied static load.