Magnetoadsorptive particles enabling the centrifugation-free, preparative-scale separation, and sorting of single-walled carbon nanotubes

A novel magnetic composition of the high surface area particles with amide chemical functionality, Sephacryl S-200, is reported enabling the preparative-scale (1 L, ≈5-10 mg) separation of metallic and semiconducting single-walled carbon nanotubes (SWNT) from completely unpurified and uncentrifuged nanotube stocks. Sephacryl S-200 has previously been utilized in separating semiconducting SWNT (s-SWNT) on the laboratory scale. Significantly, use of these magnetic derivative particles in absorptive separation of SWNT allows the unprecedented and industrially scalable purification of both metallic SWNT (m-SWNT) as well as s-SWNT directly from uncentrifuged, ultrasonicated surfactant-based SWNT solutions by simple and scalable magnetic separation. These particles also allowed for the systematic study on the effect of SWNT-polymer interaction time on the resulting SWNT "payloads." Ultimately, high-purity m-SWNT and s-SWNT products are independently achieved by controlling the SWNT-polymer interaction time and relative concentrations, as well as SWNT sonication conditions. Furthermore, by controlling these factors, single-chirality (6,5) s-SWNT can be isolated with 92% purity directly from unpurified stocks. Thermogravimetric analysis indicates a total process SWNT yield of 1.2% and 1.7% for m-SWNT and s-SWNT, respectively. These results demonstrate the potential for a preparative method for separating carbon nanotubes based on electronic properties.