Enhanced solubilization of large-diameter single-walled carbon nanotubes with amino-functionalized dipyrene nanotweezers

Abstract

Pyrene-based nanotweezers 1 consisting of two pyrenes and amino-substituted carbazole in between have been successfully synthesized via Suzuki-Miyaura coupling reaction. The supramolecular complex formation of nanotweezers 1 with single-walled carbon nanotubes (SWNTs) was studied, and it was found that nanotweezers 1 exhibited much higher the SWNTs extraction ability as compared to the analogous dipyrene nanotweezers 2 and 3 with soluble alkyl-substituents. This enhanced extraction ability of 1 can be attributed to the formation of more stable SWNT complexes in methanol. On the basis of photoluminescence excitation and UV-Vis-NIR absorption of 76-CoMoCAT SWNTs before and after the extraction, nanotweezers 1 were found to show high selectivity towards (8,4)-, (7,6)-, (9,4)-, and (8,6)-SWNTs with diameter ranging from 0.84 to 0.97 nm.

Mass Production of High-Purity Semiconducting Carbon Nanotubes by Hydrochloric Acid Assisted Gel Chromatography

“…Four medical syringes filled with 4 mL gel beads were prepared, and 2 mL of SWCNT dispersion was loaded into each gel column. As mentioned above, we washed the unbound nanotubes from the four gel columns with the eluent of 0.5 wt % SDS + 0.5 wt % SC without HCl and then eluted We also quantitatively assessed the effect of the HCl concentrations on the selective desorption of the adsorbed nanotubes by the optical absorbance of the m-SWCNTs at 456 nm (mainly contributed by (6, 6) SWCNTs) and 505 nm (mainly contributed by (7, 7) and (8, 5) SWCNTs) 28 and the s-SWCNTs at 1032, 1121, 1181, and 1257 nm and their ratio. As shown in Figure 2c, the desorption amount of both the m-and s-SWCNTs increased with an increase in the HCl concentration.…”

“…We also quantitatively assessed the effect of the HCl concentrations on the selective desorption of the adsorbed nanotubes by the optical absorbance of the m-SWCNTs at 456 nm (mainly contributed by (6, 6) SWCNTs) and 505 nm (mainly contributed by (7, 7) and (8, 5) SWCNTs) and the s-SWCNTs at 1032, 1121, 1181, and 1257 nm and their ratio. As shown in Figure c, the desorption amount of both the m- and s-SWCNTs increased with an increase in the HCl concentration.…”

Solid-Phase Debundling of Single-Walled Carbon Nanotubes for the “Stock Solid” Delivery of Concentrated Nanotube Dispersions

“…Between the two approaches developed so far for preparing SWNTs dispersions, noncovalent functionalization is considered to be superior to the covalent one in terms of preserving the conjugated structure and intrinsic properties of SWNTs. Therefore, a number of researchers have concentrated on developing novel and efficient dispersants, including surfactants, − biomolecules, − aromatic compounds, − and polymers, ,, for noncovalent functionalization of SWNTs. On the other hand, the means employed to achieve noncovalent functionalization have been mostly limited to bath and probe type sonication. ,,− Although these liquid-phase sonication based techniques are sufficient for debundling and dispersing SWNTs in various solvents in the presence of dispersant, they suffer from either low concentration or low yield (<60 μg / mL or <15%, respectively) .…”

“…Therefore, a number of researchers have concentrated on developing novel and efficient dispersants, including surfactants, − biomolecules, − aromatic compounds, − and polymers, ,, for noncovalent functionalization of SWNTs. On the other hand, the means employed to achieve noncovalent functionalization have been mostly limited to bath and probe type sonication. ,,− Although these liquid-phase sonication based techniques are sufficient for debundling and dispersing SWNTs in various solvents in the presence of dispersant, they suffer from either low concentration or low yield (<60 μg / mL or <15%, respectively) . Furthermore, the presence of solvent may make the concentration less controllable and less precise.…”

“…Since no solvent was added, the milled powder can be stored as a “stock solid” and readily dispersed in water simply by shaking with hand prior to use, avoiding the sedimentation from “stock dispersion” . These are considered to be advantages of dry ball milling over wet process including bath and probe type sonication, shearing, and wet ball milling, in terms of long-term storage. ,,,− Furthermore, through the ball milling debundling combined with shake-assisted dispersing process, about 60% SWNTs were well dispersed in H 2 O. This value is much higher than that through sonication (mostly <30%) ,,, and vibration milling mentioned above (<6%) …”