Metal/semiconductor separation of single‐wall carbon nanotubes by selective adsorption and desorption for agarose gel

Abstract

Metallic and semiconducting single-wall carbon nanotubes (SWCNTs) were separated by selective adsorption and desorption using agarose gel beads and SWCNTs/sodium dodecyl sulfate dispersion. Comparison to the batch method, the purities of metallic and semiconducting SWCNTs obtained by a column method were improved to 90 and 95%, respectively. When linear-gradient elution was applied to the column method, semiconducting SWCNTs and presumed mixed bundles could be separated into early-and late-eluted fractions, respectively. In the semiconducting fractions, chirality separation was also detected.

State of the Art of Single‐Walled Carbon Nanotube Synthesis on Surfaces

“…Though separating SWNTs in the growth process is attractive, post growth separation of SWNTs is easier to realize. Many efforts have been made to separate metallic and semiconducting SWNTs, although it is still far from satisfying the exciting application of SWNTs such as in all carbon electronic devices. Though separation in liquid phase has been well developed, directly separation on the substrate surface is more compatibility with semiconductor industry.…”

From metal/semiconductor separation to single‐chirality separation of single‐wall carbon nanotubes using gel

“…In the column separation, the adsorption was thought to occur mainly on the surface of the gel beads, where the separation was relatively unaffected by the pore size or the length of SWCNTs [17]. The diameters or chiralities were separated to some extent by changing the elution conditions of the stepwise [19] and linear gradients [20]. These column methods have many advantages in addition to providing gel-free S-SWCNTs, such as rapidity, scalability, reusability of the gel, and compatibility with automation.…”

“…3 Chirality separation using dextran-based gel The agarose gel column method was used to separate the chiralities of the S-SWCNTs in addition to M/S separation, but the resolution was not so high [19,20]. Thus, another type of polysaccharide gel, Sephacryl [30], which is composed of cross-linked dextran (allyl dextran and N,N′-methylene bisacrylamide, GE healthcare), was used for the chirality separation of the SWCNTs [21].…”

“…Recently, novel M/S separation methods have been developed using agarose gel [15][16][17][18][19][20]. Agarose is a biopolymer obtained from algae and is a gel-forming linear polysaccharide with a 1,3-β-D-galactose and 1,4-α-L-3,6-anhydro-galactose repeat unit.…”

Carbon Nanotubes Engineering Assisted by Natural Biopolymers

“…Chitosan was found to have ability for the enrichment of small-diameter semiconducting SWNTs by preserve the as-dispersed suspension overnight without centrifugation or any other physical treatment (Yang, 2006). After that, another polysaccharide agarose were introduced to separate metallic and semiconducting SWCNTs Tanaka, December 2009;Tanaka, et al 2010;Liu, et al 2010). The suspension of single dispersed SWCNTs by surfactant SDS was mixed with agarose gel for gelation.…”