The University of Southampton
University of Southampton Institutional Repository

Enrichment mechanism of semiconducting single-walled carbon nanotubes by surfactant amines

Enrichment mechanism of semiconducting single-walled carbon nanotubes by surfactant amines
Enrichment mechanism of semiconducting single-walled carbon nanotubes by surfactant amines
Utilization of single-walled carbon nanotubes (SWNTs) in high-end applications hinges on separating metallic (met-) from semiconducting (sem-) SWNTs. Surfactant amines, like octadecylamine (ODA) have proven instrumental for the selective extraction of sem-SWNTs from tetrahydrofuran (THF) nanotube suspensions. The chemical shift differences along the tail of an asymmetric, diacetylenic surfactant amine were used to probe the molecular dynamics in the presence and absence of nanotubes via NMR. The results suggest that the surfactant amine head is firmly immobilized onto the nanotube surface together with acidic water, while the aliphatic tail progressively gains larger mobility as it gets farther from the SWNT. X-ray and high-resolution TEM studies indicate that the sem-enriched sample is populated mainly by small nanotube bundles containing ca. three SWNTs. Molecular simulations in conjunction with previously determined HNO(3)/H(2)SO(4) oxidation depths for met- and sem-SWNTs indicate that the strong pinning of the amine surfactants on the sem-enriched SWNTs bundles is a result of a well-ordered arrangement of nitrate/amine salts separated with a monomolecular layer of H(2)O. Such continuous 2D arrangement of nitrate/amine salts shields the local environment adjacent to sem-enriched SWNTs bundles and maintains an acidic pH that preserves nanotube oxidation (i.e., SWNT(n+)). This, in turn, results in strong interactions with charge-balancing NO(3)(-) counterions that through their association with neutralized surfactant amines provide effective THF dispersion and consequent sem enrichment.
0002-7863
6775-6784
Ju, Sang-Yong
6d99cea5-a544-49f2-9a3f-b1347132e587
Utz, Marcel
c84ed64c-9e89-4051-af39-d401e423891b
Papadimitrakopoulos, Fotios
8de3549f-a482-441a-bb31-d1f5269d873c
Ju, Sang-Yong
6d99cea5-a544-49f2-9a3f-b1347132e587
Utz, Marcel
c84ed64c-9e89-4051-af39-d401e423891b
Papadimitrakopoulos, Fotios
8de3549f-a482-441a-bb31-d1f5269d873c

Ju, Sang-Yong, Utz, Marcel and Papadimitrakopoulos, Fotios (2009) Enrichment mechanism of semiconducting single-walled carbon nanotubes by surfactant amines. Journal of the American Chemical Society, 131 (19), 6775-6784. (doi:10.1021/ja809054c).

Record type: Article

Abstract

Utilization of single-walled carbon nanotubes (SWNTs) in high-end applications hinges on separating metallic (met-) from semiconducting (sem-) SWNTs. Surfactant amines, like octadecylamine (ODA) have proven instrumental for the selective extraction of sem-SWNTs from tetrahydrofuran (THF) nanotube suspensions. The chemical shift differences along the tail of an asymmetric, diacetylenic surfactant amine were used to probe the molecular dynamics in the presence and absence of nanotubes via NMR. The results suggest that the surfactant amine head is firmly immobilized onto the nanotube surface together with acidic water, while the aliphatic tail progressively gains larger mobility as it gets farther from the SWNT. X-ray and high-resolution TEM studies indicate that the sem-enriched sample is populated mainly by small nanotube bundles containing ca. three SWNTs. Molecular simulations in conjunction with previously determined HNO(3)/H(2)SO(4) oxidation depths for met- and sem-SWNTs indicate that the strong pinning of the amine surfactants on the sem-enriched SWNTs bundles is a result of a well-ordered arrangement of nitrate/amine salts separated with a monomolecular layer of H(2)O. Such continuous 2D arrangement of nitrate/amine salts shields the local environment adjacent to sem-enriched SWNTs bundles and maintains an acidic pH that preserves nanotube oxidation (i.e., SWNT(n+)). This, in turn, results in strong interactions with charge-balancing NO(3)(-) counterions that through their association with neutralized surfactant amines provide effective THF dispersion and consequent sem enrichment.

Full text not available from this repository.

More information

Published date: April 2009
Organisations: Chemistry

Identifiers

Local EPrints ID: 340207
URI: http://eprints.soton.ac.uk/id/eprint/340207
ISSN: 0002-7863
PURE UUID: 0f41cba4-d0b8-47b7-83a7-f14edbf36702
ORCID for Marcel Utz: ORCID iD orcid.org/0000-0003-2274-9672

Catalogue record

Date deposited: 15 Jun 2012 08:54
Last modified: 03 Dec 2019 01:37

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×