Separation of metallic single‐walled carbon nanotubes using various amines

Abstract

Separation of metallic single-walled carbon nanotubes (m-SWNTs) using various amines in different concentrations was investigated. The SWNTs dispersions were characterized with Vis-NIR and Raman spectrometers. The proportion of m-SWNTs toward semiconducting SWNTs increased with an increase of concentration of amines. SWNTs thin films were prepared from the SWNTs dispersion. The sheet resistance of SWNTs films decreased with an increase of proportion of m-SWNTs. We have already reported the effective dispersion of SWNTs into organic solvents by using amines as dispersant reagents [3]. Interestingly, m-SWNTs were selectively extracted into a tetrahydrofuran (THF) solution containing propylamine in high concentration. Herein, we report separation of m-SWNTs using various amines in different concentrations. The preparation of transparent and

Direct Intermolecular Force Measurements between Functional Groups and Individual Metallic or Semiconducting Single‐Walled Carbon Nanotubes

“…For example, with unfunctionalized gold probe (Figure a), there is little difference in the mean adhesion force (mean +/‐ one standard deviation) between the S (26.7 ± 3.1 nN) and M (28.0 ± 3.8 nN) nanotubes, indicating that gold does not exhibit preferential selectivity for metallic or semiconducting SWNTs. The force histograms measured with the three functionalities (Figure b–d) differ significantly from those of the non‐functionalized probe, corroborating that some of these functionalities have SWNT metallicity selectivity, confirming determinations by others made using indirect methods …”

“…Various functional groups, specifically amine, naphthalene and pyrene (Figure b) were used for tip functionalization in demonstration of this direct force measurement technique. These functional groups have been found (theoretically or experimentally in the presence of other molecules such as surfactants and solvents) to have metallicity‐dependent SWNT selectivity …”

Fullertubes: Cylindrical Carbon with Half-Fullerene End-Caps and Tubular Graphene Belts, Their Chemical Enrichment, Crystallography of Pristine C90-D5h(1) and C100-D5d(1) Fullertubes, and Isolation of C108, C120, C132, and C156 Cages of Unknown Structures

“…In this first stage, the high reactivity of primary amines with spheroidal fullerenes renders their cages hydrophilic for removal. − (It is interesting to note that functionalized amines were used to separate metallic from semiconducting nanotubes. ) − Our second stage requires only one column for C 90 , C 96 , and C 100 fullertube isolation. HPLC purification is rapid, cost-effective, facile, and green (i.e., less solvent, less money, less time, and less chemical waste).…”

High-Concentration Aqueous Dispersions of Graphene Using Nonionic, Biocompatible Block Copolymers

“…Previous studies employing aminated dispersing agents to exfoliate carbon nanotubes have demonstrated increased affinity of amine groups for metallic carbon nanotubes. 23,24 Similar interactions with zero bandgap graphene nanoplatelets could explain the increased affinity of Tetronics. Interestingly, Tetronic 304, which is the smallest molecular weight copolymer tested, displayed dispersion efficiencies comparable to much higher molecular weight copolymers such as Pluronic F88 and Tetronic 908.…”