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Title: Selective Surface Charge Sign Reversal on Metallic Carbon Nanotubes for Facile Ultrahigh Purity Nanotube Sorting
Authors: Wang, Jing
Nguyen, Tuan Dat
Cao, Qing
Wang, Yilei
Tan, Marcus Y.C.
Chan-Park, Mary B.
Keywords: Carbon nanotubes
Gel chromatography
Issue Date: 2016
Source: Wang, J., Nguyen, T. D., Cao, Q., Wang, Y., Tan, M. Y., & Chan-Park, M. B. (2016). Selective Surface Charge Sign Reversal on Metallic Carbon Nanotubes for Facile Ultrahigh Purity Nanotube Sorting. ACS Nano, 10(3), 3222-3232.
Series/Report no.: ACS Nano
Abstract: Semiconducting (semi-) single-walled carbon nanotubes (SWNTs) must be purified of their metallic (met-) counterparts for most applications including nanoelectronics, solar cells, chemical sensors, and artificial skins. Previous bulk sorting techniques are based on subtle contrasts between properties of different nanotube/dispersing agent complexes. We report here a method which directly exploits the nanotube band structure differences. For the heterogeneous redox reaction of SWNTs with oxygen/water couple, the aqueous pH can be tuned so that the redox kinetics is determined by the availability of nanotube electrons only at/near the Fermi level, as predicted quantitatively by the Marcus–Gerischer (MG) theory. Consequently, met-SWNTs oxidize much faster than semi-SWNTs and only met-SWNTs selectively reverse the sign of their measured surface zeta potential from negative to positive at the optimized acidic pH when suspended with nonionic surfactants. By passing the redox-reacted nanotubes through anionic hydrogel beads, we isolate semi-SWNTs to record high electrically verified purity above 99.94% ± 0.04%. This facile charge sign reversal (CSR)-based sorting technique is robust and can sort SWNTs with a broad diameter range.
ISSN: 1936-0851
DOI: 10.1021/acsnano.5b05795
Schools: School of Chemical and Biomedical Engineering 
Rights: © 2016 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by ACS Nano, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [].
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:SCBE Journal Articles

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