Mass separation of metallic and semiconducting single‐wall carbon nanotubes using agarose gel

Metallic and semiconducting single‐wall carbon nanotubes (SWCNTs) were separated using agarose gel. When the SWCNTs isolated with sodium dodecyl sulfate (SDS) were embedded in agarose gel, the metallic SWCNTs were eluted from the gel by applying electronic field or mechanical stress, for example, centrifugation etc., and semiconducting SWCNTs remained in the gel. The purities for metallic and semiconducting SWCNTs were ∼70% and ∼95%, respectively. One of the simplest methods was freeze, thaw and squeeze the SWCNTs containing gel. These methods can separate various kinds of SWCNTs. By using centrifugation method, we could separate about 10 mg of SWCNTs with a 500 ml bottle.