Functionalization of Carbon Nanotubes

Ames Research Center, Moffett Field, California

Carbon nanotubes (CNTs) have attracted much attention due to their extraordinary mechanical and unique electronic properties. CNTs are being studied for applications in high-strength/low-weight composites and other applications. In order to alter the CNT properties for particular applications, chemical functionalization may be necessary. Development of multifunctional composite materials may require functionalization of a collection of CNTs to allow the tubes to be dispersed more easily in a host matrix.

For many applications of nanotubes in sensors, composites, and other nano devices, chemical functionalization of the nanotubes is necessary. A common approach to functionalize nanotubes is to use a wet chemical procedure or electrochemical procedure. A patented method and system for dry chemical functionalization of a collection of CNTs was developed. This technology is a clean and efficient approach that uses a plasma or glow discharge to functionalize the nanotubes with atomic or molecular chemical species. The method can use direct current, radio frequency (inductive or capacitive), or microwave sources to strike a glow discharge and generate a large number of species needed for functionalization from appropriate source gases.

This technology provides a selective, scalable approach not involving “wet” chemistry, for functionalization of a collection of CNTs with any of a large class of elements and compounds, including hydrogen, alkali metals, selected hydrocarbons, selected organic species, and halogens. A selected precursor gas is irradiated to provide a cold plasma of selected target species in a first chamber. The target species are directed toward an array of CNTs located in a second chamber. A CNT array is functionalized with the target species — at room temperature — to a point of saturation very rapidly, making it an efficient method to functionalize CNTs.

This work was done by Meyya Meyyappan of Ames Research Center and Bishun N. Khare of SETI Institute. NASA is actively seeking licensees to commercialize this technology. Please contact Trupti Sanghani at This email address is being protected from spambots. You need JavaScript enabled to view it. or 650-604-6889 to initiate licensing discussions. Follow this link for more information: here .