Abstract
Despite the relative ease with which carbon nanotubes can be synthesized, controlling and optimizing their growth constitutes a grand challenge in nanoscience. From a practical standpoint, precise control over nanotube length is essential for their application in electronic devices or sensors while understanding how to grow long nanotubes at high rates is a major production challenge for their use in composites.
However, few in situ diagnostic probes of nanotube growth have been developed, so growth kinetics measurements have not been made and growth models await testing and verification. Recent in situ diagnostic experiments will be described which are providing some of the first direct measurements of growth rates and kinetics during both laser-vaporization synthesis and chemical vapor deposition of carbon nanotubes - information which is helping to understand nanotube growth mechanisms and kinetics, and why nanotube growth terminates. Using these techniques, vertically-aligned arrays of multiwall carbon nanotubes have been grown to millimeter lengths at high rates for use in multifunctional polymer composites. The new facilities at ORNL's Center for Nanophase Materials Sciences (CNMS) for the controlled growth and development of functional nanomaterials will also be described.
