SBIR Phase I: Spiral Countercurrent Chromatography for the Separation of Carbon Nanotubes

The broader impact/commercial potential of this project lies in the availability of single-wall carbon nanotubes in their most highly purified form in laboratory scale quantities. This would be enabled by the use of a spiral countercurrent chromatograph, invented and made in the USA. Single-wall carbon nanotube is one of the most promising semi-conductor materials and is being actively considered for making state-of-the-art high performance electronic circuits. The associated know-how will be of great value to the high volume semi-conductor manufacturing industry. The availability of discrete chiral types of the single-wall carbon nanotubes separated by the proposed system will have additional impact on the research market. Research labs in the semi-conductor industry and academic labs may be able to develop the carbon nanotube based nanomaterials, components and final products for point of care diagnostics, genomics devices and sensors for environmental and security identification. The societal benefits of these potential applications are significant. The benefits extend more broadly to the life science research industry also where the technology works for protein and particle separations in the development of novel vaccines and drug delivery. This Small Business Innovation Research (SBIR) Phase I project focuses on developing a novel laboratory scale system for carbon nanotube purification. Carbon nanotubes are challenging to manufacture and isolate in their pure form for use as robust logic and sensor elements in advanced electronics. They are hard crystal carbon polymers that are heterogeneous tubes of various lengths and diameters and occur as single-walled or multi-walled with other structures. The existing processes to solubilize and purify the various single-walled semi-conductor species are quite difficult and have low mass yields. The methods mostly used to date are column chromatography and density gradient ultracentrifugation. To meet the need of higher mass loading and increased selectivity, this proposal focuses on developing spiral countercurrent chromatography. A new spiral design rotor used with a polymer solvent mix has shown improved nanotube fractionation over static extraction in preliminary experiments. Recent innovative research on dextran polymer liquid stationary phase makes it possible to improve the fractionation of carbon nanotubes even further. It also opens up many exciting options for large molecule separation. This development has a very significant intellectual merit for both chromatography and semi-conductor research.