Diameter-Selective Metal/Semiconductor Separation of Single-wall Carbon Nanotubes by Agarose Gel

Abstract

The separation of semiconducting and metallic single-wall carbon nanotubes (SWCNTs) by agarose gel chromatography was investigated. SWCNTs dispersed in sodium dodecyl sulfate (SDS) solution were applied to the top of the gel column. Metallic SWCNTs were eluted with SDS solution. Subsequently, the semiconducting SWCNTs that remained in the gel column were collected with sodium deoxycholate (DOC) solution as the eluant. By the successive addition of DOC solutions with concentrations ranging from 0.05 to 2 wt % and fractional collection at each concentration, we found that smaller-diameter enriched S-SWCNTs were eluted first with the lower concentration DOC solutions and then larger-diameter enriched S-SWCNTs were eluted with the higher DOC concentration solutions. Thus, diameter-selective enrichment of semiconducting SWCNTs was achieved. Diameter-selective enrichment of metallic SWCNTs was also demonstrated by adding a series of SDS solutions with different concentrations. These results demonstrate that agarose gel can be used to simultaneously separate metallic and semiconducting SWCNTs and to perform diameter separation of these SWCNTs.