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.
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.
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 techniques discussed include thermogravimetric analysis; near-infrared spectroscopy; Raman spectroscopy and optical, electron and scanned probe microscopy.
COMPAMED.de; Source: National Institute of Standards and Technology