1 9711785 Smalley The objective of this Selected Research Opportunity Grant is to interrogate the true tensile strength of an individual single-wall carbon nanotube (SWNT). Achieving these very difficult experiments will require substantial improvements in techniques for isolating, manipulating, and securing SWNT ropes onto fabricated supports. A single continuous rope of SWNTs will be draped cross metallic line features on a silicon wafer fabricated at the Stanford Nanofabrication Facility. The sample will then be introduced into an atomic force microscope which will be used for three purposes: (1) The entire sample will be scanned periodically, first to find an attractive span, and subsequently to look for signs of breakage and slippage; (2) High-resolution scans of the rope lying on the support lines on either side of the span will yield the geometry of the rope, giving a good estimate for the number of SWNTs in the rope; (3) The AFM tip will be engaged at one point in the middle of the span to deflect the rope. The known AFM cantilever force constant along with the measured deflections will provide the information required to obtain tensile strengths of the rope and of the individual tubes. %%% New evidence suggests that carbon nanotubes are the strongest materials known, potentially enabling unique applications in many areas critical to the U.S. economy. This research will involve direct measurements of the strength of nanotube ropes using micromanipulators. The results will provide the foundation for research and development of nanotube based superstrong materials and their applications
