Editorial Feature

Carbon Nanotubes - Definition, Properties, Industry Applications and Possible Environmental Concerns

Carbon nanotubes are large molecules of pure carbon that are long and thin and shaped like tubes, about 1-3 nanometers (1 nm = 1 billionth of a meter) in diameter, and hundreds to thousands of nanometers long. As individual molecules, nanotubes are 100 times stronger-than-steel and one-sixth its weight. Some carbon nanotubes can be extremely efficient conductors of electricity and heat; depending on their configuration, some act as semiconductors.

Industry Applications for Carbon Nanotubes

Some people believe that nanotubes are one of nanotech’s most promising molecular building blocks because they exhibit unique properties with a wide range of potential commercial applications. Industry enthusiasts believe that carbon nanotubes will radically improve the performance of tiny sensors, electronic and optical devices, catalysts, batteries, fuel cells, solar cells and drug delivery vehicles. Currently 50% of all lithium batteries incorporate carbon nanofibers (wires spun from carbon nanotubes), which double their energy capacity. Some predict that nano-scale carbon transistors will replace silicon transistors within the next decade. Nanotubes are already used in tennis rackets to make them stronger and lighter. Fortifying a bulletproof vest with a small quantity of nanotubes could double its ability to absorb the energy of a bullet. One company is developing carbon nanotubes to make plastics fire retardant. Carbon nanotubes are capable of storing up to 65 percent of their weight in hydrogen - a capacity that could someday make hydrogen fuel cells a cheap and efficient alternative to fossil fuels. Scientists at Rice University are developing a new type of wire made of carbon nanotubes that conducts electricity much better than copper, and could transform the electrical power grid.

The Market for Carbon Nanotubes All Depends on Industry’s Ability to Mass-Produce Nanotubes

The huge potential market for carbon nanotubes hinges on industry’s ability to figure out how to produce large quantities of carbon nanotubes more cheaply and uniformly. Today, there are at least three major processes for producing carbon nanotubes, but most companies measure output in only grams per day.

A Report by Cientifica Outlines the Way Ahead for the Mass-Production of Carbon Nanotubes

According to a 2005 report from nanotech industry analysts, Cientifica, the nanotube market is poised for big changes. “Massive improvements in capacity are now such that demand for nanotubes will no longer be constrained by production,” predicts Cientifica. A total of 65 tons of nanotubes and nanofibers were produced in 2004 with a market value of roughly €144 million. Cientifica predicts that by 2010 carbon nanotube prices will decrease by a factor of 10-100, the global market for nanotubes will surpass €3 billion and Korea will be the major supplier of all types of nanotubes.

Current Debate Concerning the Possible Toxicity of Carbon Nanotubes

Despite the huge amount of interest and investment in carbon nanotubes, the toxicological impacts of these and other engineered nanoparticles are still unknown. A handful of toxicological studies reported thus far indicate that there is reason for concern. In 2005, researchers at the US National Aeronautic and Space Administration (NASA) reported that when commercially available carbon nanotubes were injected into the lungs of rats it caused significant lung damage. (The researchers indicated that the nanotube dosage applied to rats was roughly equivalent to worker exposure levels over a 17-day period.) In a separate study, researchers at the US National Institute of Occupational Safety and Health reported in 2005 substantial DNA damage in the heart and aortic artery of mice that were exposed to carbon nanotubes.

Note: A complete set of references can be found by referring to the original document.  

Sources and Further Reading

  • ETC Group report entitled ‘Nanotech’s “Second Nature” Patents: Implications for the Global South’, April/May 2005.

Note: A complete set of references can be found by referring to the original document

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