Spatial Variations in the Mechanical Properties and Electrical Properties of Carbon Nanotube Turfs

Abstract

AbstractThe mechanical properties of arrays of nominally vertically aligned carbon nanotubes, often referred to as turfs, have been measured using nanoindentation and the electrical properties have been measured using electrical contact resistance (ECR) nanoindentation. The elastic properties do not vary significantly between the top and the bottom of the same carbon nanotube turf. Within a single turf the lateral spatial variation is less than 10% when volumes of μm's are probed with the indenter, indicating that each turf can be treated mechanically as continuum on this scale. The electrical properties vary significantly within a single turf on the same scale. This suggests that the use of average mechanical properties for a given vertically aligned turf should be suitable for design purposes without the need to account for spatial variation in structure, and variations in mechanical properties on the micrometer scale are not dependent on spatially distinct defects. However, local contact behavior appears to dominate the electrical behavior on this same length scale.