• carbon nanotubes;
  • magnetic separation;
  • polymers;
  • superparamagnetic;
  • carbon nanotube separation

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.