The Ultimate Strength of Carbon Nanotubes

1 9711785斯马利这项选定的研究机会补助金的目的是询问单个单壁碳纳米管的真实抗拉强度。要实现这些非常困难的实验，将需要在隔离、操纵和固定SWNT绳索到预制支架上的技术方面有实质性的改进。在斯坦福纳米加工设施制造的硅晶片上，单根连续的单壁碳纳米管绳索将被覆盖在交叉金属线特征上。然后，样品将被引入原子力显微镜，用于三个目的：(1)定期扫描整个样品，首先寻找有吸引力的跨度，然后寻找断裂和滑动的迹象；(2)对跨度两侧支撑线上的绳子进行高分辨率扫描，将得到绳子的几何形状，从而很好地估计绳子中的单壁碳纳米管的数量；(3)AFM尖端将在跨度中间的一点啮合，以使绳子偏转。已知的AFM悬臂力常数以及测量的挠度将提供获得绳索和单个管子的抗拉强度所需的信息。%新证据表明，碳纳米管是已知的最坚固的材料，有可能在许多对美国经济至关重要的领域实现独特的应用。这项研究将包括使用微操作器直接测量纳米管绳的强度。研究结果将为纳米管基超强材料及其应用的研究和开发提供基础

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