Dispersion of arc-discharged single-walled carbon nanotubes using the natural α-amino acid derivative N-dodecanoyl leucinate

Abstract

The synthesized natural α-amino acid derivative N-dodecanoyl leucinate demonstrates an effective and selective dispersion towards arc-discharged SWNTs.

Polymethyl(1–Butyric acidyl)silane–Assisted Dispersion and Density Gradient Ultracentrifugation Separation of Single–Walled Carbon Nanotubes

“…As a matter of fact, the peak absorbance (A) correlates with the concentration of SWNTs (c in mg/mL) through Beers law (A = εlc), where ε is the extinction coefficient (mL/mg.cm) and l is the path length (1 cm in this work). Considering the data reported previously [26], i.e., ε is 52.04 and 60.59 mL/mg.cm for m-and sc-SWNTs, respectively, the purity of m-SWNTs in the top green layer is estimated to be 85.6%. As for the s-SWNT in the bottom red-brown layer, it is impossible to estimate their purity by the same method, since the effective M 11 transition from the m-SWNTs is not visible and therefore cannot be measured owing to the low sensitivity of absorption spectroscopy and error propagation.…”

“…Aiming at the separation of SWNTs with different electronic types, a cosurfactant mixture was applied to achieve a change in the buoyant densities between m-and sc-SWNTs [26,51,64,65]. As shown in Scheme 2, the effective individualization of arc-discharged SWNTs was realized by ultrasonic dispersion in the aqueous solution of a branched linear chain surfactant BA-PMS molecules.…”

“…Since the CH-π interaction between SDS and SWNTs is stronger than that between BA-PMS and SWNTs, the adsorbed BA-PMS molecules are expected to be easily replaced by SDS. Considering the lower molar volume of SDS than BA-PMS and the larger water cluster around the hydrated sulfonic acid groups than that around the hydrated carboxyl groups [26,51,64,65], the replacement of BA-PMS by SDS would result in a decrease in the buoyant density of the tube-surfactant complex. On the other hand, quite different from sc-SWNTs there are some free electrons in the Fermi level of m-SWNTs, and the CH-π interactions between SDS and m-SWNTs must be stronger than that between SDS and sc-SWNTs.…”

“…For non-covalent chemical modifications, the choice of dispersing agents is crucial to the effective individualization and efficient sorting of metallic or semiconducting SWNTs. Typical dispersing agents are limited to classic surfactants [22][23][24], ionic liquids [25], and biological substances [12,26,27] applicable in water media as well as varying polymers [28][29][30] applicable in water or non-water media. In the case of polymers, both the water-soluble nonaromatic species [31][32][33] and the non-water-soluble π-conjugated ones are selective for sc-SWNTs [34][35][36][37].…”

Enrichment of high-purity large-diameter semiconducting single-walled carbon nanotubes

“…Large-diameter s-SWCNTs ( plasma-torch, arc-discharge and Tuball) tend to be longer, straighter, and have fewer defects, exhibiting higher charge carrier mobility. 24 s-SWCNTs with diameters larger than 1.2 nm have reduced Schottky barrier with the contact metal, which is helpful to increase carrier tunneling and decrease on-state resistance. 25 Therefore, large-diameter SWCNTs are important building blocks for electronic applications requiring high current density and high charge carrier mobility, such as high-performance computing (optimal d: ∼1.5 nm 26 ), thin-film transistors (TFTs), thermoelectrics, etc.…”