U.S. Develops New Technology to Cut Carbon Nanotubes

The US Rice University released a press communique on the 22nd that the university’s researchers have newly developed a fluorination pyrolysis technology. With this new technology, carbon nanotubes can be sheared into shorter fragments.
When using this new technology, thousands of fluorine atoms are first attached to the carbon nanotube wall, and then placed in argon gas and heated to about 1000 degrees Celsius. In this process, the carbon nanotubes are “cropped” into lengths. Fragments between 20 nanometers and 300 nanometers.
Carbon nanotubes are long, hollow carbon nanotubes that are formed by coiling graphene carbon atoms. They are usually several nanometers to several tens of nanometers in diameter (one nanometer is one billionth of a meter), and the length is generally several thousand nanometers. Carbon nanotubes have many novel properties, such as high toughness and high electrical conductivity, and thus have great potential for application in many fields. The application of carbon nanotubes is inseparable from various processing technologies such as shearing and classification.
The team led by Professor Ricegrave at Rice University conducted experiments and comparisons on various shear technologies and found that the fluorination and pyrolysis technology works well. Margrave explained that although most chemical techniques can also cut carbon nanotubes into fragments, the length of these fragments usually changes randomly. With fluorination pyrolysis technology, the length of carbon nanotubes after “cutting” can be controlled more effectively. In their research, they discovered that by changing the ratio between fluorine atoms and carbon atoms in nanotubes, it is possible to control the amount of "cut out" pieces of carbon nanotubes of a specific length. For example, they found that when a specific ratio between fluorine atoms and carbon atoms is reached, a 20-nm-long fragment can account for about 40% of all carbon nanotube fragments that are finally “cropped.”
The researchers said that 20-nanometer-long carbon nanotubes are smaller than many large proteins in human blood. Micro-biomedical sensors made from these carbon nanotubes will be able to walk between cells without causing immune reactions. .