Carbon nanotube measurements: latest in NIST 'how-to' seriesApril 16, 2008The National Institute of Standards and Technology (NIST), in collaboration with the National Aeronautics and Space Administration (NASA), has published detailed guidelines* for making essential measurements on samples of single-walled carbon nanotubes (SWCNTs). The new guide constitutes the current "best practices" for characterizing one of the most promising and heavily studied of the new generation of nanoscale materials. The nanotubes are essentially cylinders of carbon atoms with a wall only one atom thick and a diameter of a couple of nanometers-but lengths up to several million times their diameter. (Think of a soup can about 100 kilometers tall.) Because of their unique electronic, thermal, optical and mechanical properties they are being studied for a wide-and expanding-range of applications, including ultrastrong fibers for nanocomposite materials, circuit elements in molecular electronics, hydrogen storage components for fuel cells and light sources for compact, efficient flat-panel displays. One basic problem is assuring the quality and purity of SWCNT materials. All known techniques for producing these tiny tubes also produce large quantities of nanojunk: simple graphite and carbon soot often encapsulating small metal particles used to catalyze the nanotube synthesis process. (See, for example, "NIST Laser-Based Method Cleans Up Grubby Nanotubes", Tech Beat Dec. 1, 2006.) Accurate, reliable and preferably rapid measurement techniques are needed to optimize production processes to create more product and less impurities. These will help to control cleaning and purifying processes and ultimately to improve the confidence of buyers and sellers of SWCNT materials. Beginning in 2003, NIST and NASA researchers started addressing the problem by sponsoring a series of workshops devoted to nanotube measurements. The NIST "Recommended Practice Guide" on Measurement Issues in Single Wall Carbon Nanotubes grew out of second workshop in 2005, and represents what industry, government and academic researchers regard as the most useful and accurate measurement techniques for characterizing the purity of SWCNT samples. The techniques discussed include thermogravimetric analysis; near-infrared spectroscopy; Raman spectroscopy and optical, electron and scanned probe microscopy. Researchers from the NASA Johnson Space Center, the University of California at Riverside, Boston University and the NASA Langley Research Center contributed to the guide. The techniques described in the guide were proposed as the basis for international standards for nanotube characterization. A collaborative effort that includes the US, China, Japan, and Korea is now underway under the International Organization for Standardization (ISO) to develop these techniques into standards that will help ensure uniform characterization metrics used when buying and selling nanotubes. The editors caution that in the fast-moving field of carbon nanotubes, characterization methods will need to be updated periodically. The NIST Recommend Practice Guides are a set of publications devoted to specific, challenging measurement issues faced in industry and research. Online copies of Measurement Issues in Single Wall Carbon Nanotubes and other guides in the series are available at The "How To Measure" Book Series. ### * S. Freiman, S. Hooker, K. Migler and S. Arepalli (eds.). Measurement Issues in Single Wall Carbon Nanotubes. NIST Special Publication 960-19, March 2008. National Institute of Standards and Technology (NIST) |
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| Related Carbon Nanotubes Current Events and Carbon Nanotubes News Articles Breakthrough in industrial-scale nanotube processing Rice University scientists today unveiled a method for the industrial-scale processing of pure carbon-nanotube fibers that could lead to revolutionary advances in materials science, power distribution and nanoelectronics. Next-generation microcapsules deliver 'chemicals on demand' Scientists in California are reporting development of a new generation of the microcapsules used in carbon-free copy paper, in which capsules burst and release ink with pressure from a pen. Study shows how carbon nanotubes can affect lining of the lungs Carbon nanotubes are being considered for use in everything from sports equipment to medical applications, but a great deal remains unknown about whether these materials cause respiratory or other health problems. Advance in 'nano-agriculture': Tiny stuff has huge effect on plant growth With potential adverse health and environmental effects often in the news about nanotechnology, scientists in Arkansas are reporting that carbon nanotubes (CNTs) could have beneficial effects in agriculture. A recipe for controlling carbon nanotubes Nanoscopic tubes made of a lattice of carbon just a single atom deep hold promise for delivering medicines directly to a tumor, sensors so keen they detect the arrival or departure of a single electron, a replacement for costly platinum in fuel cells or as energy‐saving transistors and wires. Friction force differences could offer a new means for sorting and assembling nanotubes Nanotubes and nanowires are promising building blocks for future integrated nanoelectronic and photonic circuits, nanosensors, interconnects and electro-mechanical nanodevices. But some fundamental issues remain to be resolved - among them, how to position and manipulate the tiny tubes. New biosensor can detect bacteria instantaneously A research group from the Rovira i Virgili University (URV) in Tarragona has developed a biosensor that can immediately detect very low levels of Salmonella typhi, the bacteria that causes typhoid fever. Researchers design new graphene-based, nano-material with magnetic properties An international team of researchers has designed a new graphite-based, magnetic nano-material that acts as a semiconductor and could help material scientists create the next generation of electronic devices like microchips. Researchers Pinpoint Neural Nanoblockers in Carbon Nanotubes A team of Brown University scientists has pinpointed why carbon nanotubes tend to block a critical signaling pathway in neurons. Pitt researchers harness carbon nanomaterials for drug delivery systems, oxygen sensors Two nanoscale devices recently reported by University of Pittsburgh researchers in two separate journals harness the potential of carbon nanomaterials to enhance technologies for drug or imaging agent delivery and energy storage systems, in one case, and, in the other, bolster the sensitivity of oxygen sensors essential in confined settings, from mines to spacecrafts. More Carbon Nanotubes Current Events and Carbon Nanotubes News Articles |
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