U.S. government scientists say they have developed a new method of rapidly assessing the quality of carbon nanotubes.
Researchers at the National Institute of Standards and Technology say initial feasibility tests show the method not only is faster than the standard analytic technique, but also effectively screens much smaller samples for purity and consistency and better detects sample variability.
Carbon nanotubes have unique properties, as well as thermal and electrical conductance, that could be useful in fields such as aerospace, microelectronics and biotechnology. However, those properties vary widely depending on nanotube dimensions, uniformity and chemical purity.
The new NIST method involves spraying nanotube coatings onto a quartz crystal, gradually heating the coated crystal, and measuring the change in its resonant frequency as different forms of carbon vaporize.
The frequency changes in proportion to the mass of the coating, and scientists use that as a measure of stability at different temperatures to gauge consistency among samples.
The quartz crystal technique, which can reveal mass changes of just a few nanograms, already is used in other contexts to detect toxic gases and measure molecular interactions.
The new application was presented last month during a scientific conference in Florida.
