Structure Sorting of Large‐Diameter Carbon Nanotubes by NaOH Tuning the Interactions between Nanotubes and Gel

Abstract

The structure separation of synthetic single-wall carbon nanotube (SWCNT) mixture species with diameters larger than 1.2 nm still remains a challenge. Here, an NaOH-assisted gel chromatography method is used for the structure separation of the SWCNT mixture with a diameter range of 1.2-1.7 nm, in which NaOH is used to tune the interaction between distinct (n, m) SWCNTs and gel. Incrementally increasing NaOH concentration in SWCNT dispersion selectively enhances the adsorbability of different-structure SWCNTs and enlarges their interaction difference with gel, leading to their structure separation after applying into a gel column system. On this basis, a two-step method is developed for further improving the structure purity of the separated SWCNTs by combining overloading and stepwise elution. These results are well demonstrated by the optical spectra of the separated SWCNTs. This work paves a way for single-chirality separation of largediameter SWCNTs using gel chromatography technique and is an advanced progress in the structure control of SWCNTs.

Exploiting the Physiochemical Interactions between Single-Walled Carbon Nanotubes and Hydrogel Microspheres To Afford Chirally Pure Nanotubes

“…Mechanistic insight into this correlation should also necessarily consider the thermodynamically driven nature of the SWNT desorption process, which has been demonstrated experimentally by the irreversible nature of SWNT/gel binding in the presence of 70 mM SDS. Specifically, SWNT bound to Sephacryl is not released upon the addition of neat 70 mM SDS but rather only in the presence of additional dielectric screening (introduction of 175 mM SDS or NaCl/SDS mixtures) does a fraction of the SWNT desorb from the gel. ,− This observation demonstrates that a thermodynamic stability, as opposed to a kinetic equilibrium due to a gradient in SWNT concentration, is responsible for driving the process of SWNT desorption from gels.…”

Determination of Enantiomeric Purity of Single-Wall Carbon Nanotubes Using Flavin Mononucleotide

“…We can prepare higher purity but a tiny amount of the (11,–5) SWCNTs with a CD norm value of 93 mdeg by controlling the pH in gel chromatography as described in recent work . By comparing the absorption spectra (Figure S10), we found that the samples used in this work contain impurities, such as amorphous carbon, which causes additional background absorption.…”

Gel Chromatography for Separation of Single-Walled Carbon Nanotubes

“…SWNTs with large diameters (such as arc-discharged SWNTs) have little curvature difference and narrow diameter distributions among the type of nanotubes; thus, their separation according to chirality has not been successful. Nevertheless, Yang et al successfully separated s-SWNTs according to their diameters with pH control and multi-column chromatography [ 128 ]. Oxidation of SWNTs occurs not only through the addition of acidic solutions but also by changes in the temperature of the aqueous solution.…”