2015-05-042015-05-042006-07-11Smalley, Richard E., Hauge, Robert H., Kittrell, Carter W., Sivarajan, Ramesh, Strano, Michael S., Bachilo, Sergei M. and Weisman, R. Bruce, "Method for separating single-wall carbon nanotubes and compositions thereof." Patent US7074310B2. issued 2006-07-11. Retrieved from <a href="https://hdl.handle.net/1911/79917">https://hdl.handle.net/1911/79917</a>.https://hdl.handle.net/1911/79917The invention relates to a process for sorting and separating a mixture of (n, m) type single-wall carbon nanotubes according to (n, m) type. A mixture of (n, m) type single-wall carbon nanotubes is suspended such that the single-wall carbon nanotubes are individually dispersed. The nanotube suspension can be done in a surfactant-water solution and the surfactant surrounding the nanotubes keeps the nanotube isolated and from aggregating with other nanotubes. The nanotube suspension is acidified to protonate a fraction of the nanotubes. An electric field is applied and the protonated nanotubes migrate in the electric fields at different rates dependent on their (n, m) type. Fractions of nanotubes are collected at different fractionation times. The process of protonation, applying an electric field, and fractionation is repeated at increasingly higher pH to separated the (n, m) nanotube mixture into individual (n, m) nanotube fractions. The separation enables new electronic devices requiring selected (n, m) nanotube types.42 ppengUtility patentUS7074310B2