P. Dickrell, W. G. Sawyer, University of Florida, Gainesville, FL
This report examines highly anisotropic tribological behavior of multiwalled nanotube films oriented in mutually orthogonal directions. The average values of coefficient of friction varied from extremely high values (µ=0.795) for vertically aligned nanotubes grown on rigid substrates to very low values (µ=0.090) for nanotubes dispersed flat on the same substrates. The results were insensitive to humidity, in contrast to graphite materials, and indicate that nanotubes could be utilized as both super-low and super-high frictional surfaces. Micro-brushes of vertical nanotubes fabricated in polymer embeds show enormous adhesive forces, orders of magnitude larger than well-known super-adhesives, such as Gecko-hairs found in nature.
Summary: This report examines highly anisotropic tribological behavior of multiwalled nanotube films oriented in mutually orthogonal directions. The average values of coefficient of friction varied from extremely high values (µ=0.795) for vertically aligned nanotubes grown on rigid substrates to very low values (µ=0.090) for nanotubes dispersed flat on the same substrates.