High-Resolution Length Fractionation of Surfactant-Dispersed Carbon Nanotubes

Khripin, Constantine Y.; Tu, Xiaowei; Heddleston, John M.; Silvera-Batista, Carlos A.; Walker, Angela R. Hight; Fagan, Jeffrey; Zheng, Ming

doi:10.1021/ac303349q

Cited by 53 publications

(74 citation statements)

References 35 publications

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“…Since all counting experiments were performed at 12.9 kW/cm 2 , this suggests that we did not systematically undercount dim nanotubes. Inspection of SWCNT absorption spectra shows distinct nanotube peaks with relatively low background (Figure S7), indicating that the sample did not contain a large fraction of defective and thus dark SWCNTs 33,34 . When counting both the ss(CCG) 4 -(9,4) and ss(GT) 6 -(8,6) enriched samples, the number of nanotubes detected in the gels scaled linearly with dilution factor, with r 2 values of 0.97.…”

Section: Resultsmentioning

confidence: 99%

Single Nanotube Spectral Imaging To Determine Molar Concentrations of Isolated Carbon Nanotube Species

et al. 2017

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Electronic and biological applications of carbon nanotubes can be highly dependent on the species (chirality) of nanotube, purity, and concentration. Existing bulk methods, such as absorbance spectroscopy can quantify SP2 carbon based on spectral bands, but nanotube length distribution, defects, and carbonaceous impurities can complicate quantification of individual particles. We present a general method to relate the optical density of a photoluminescent nanotube sample to the number of individual nanotubes. By acquiring 3-dimensional images of nanotubes embedded in a gel matrix with a reducing environment, we quantified the individual nanotubes in a volume, resulting in a measurement of all emissive nanotubes. Via spectral imaging, we assessed structural impurities and precisely determined molar concentrations of the (8,6) and (9,4) nanotube species. We developed an approach to obtain the molarity of any structurally-enriched semiconducting single-walled carbon nanotube preparation on a per-nanotube basis.

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Section: Resultsmentioning

confidence: 99%

Single Nanotube Spectral Imaging To Determine Molar Concentrations of Isolated Carbon Nanotube Species

et al. 2017

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“…It is generally appreciated that these property changes depend strongly on the structural parameters of the individual CNTs, such as their shape (e.g., CNT persistence length or other measure of CNT undulation scale), length, or diameter, as well as their degree of dispersion in the polymeric matrix 5 . While it is possible to synthesize long and relatively straight CNTs 6 , and even to separate single wall CNT by length 7 and chirality 8 , commercial CNT materials produced by chemical vapor deposition (CVD) are commonly composed of CNT-rich domains having a highly irregular internal structure [9][10][11] . It is often unclear whether these are aggregated CNTs having a worm-like cylinder morphology or are instead inherently branched carbon materials as found with carbon black 12 .…”

Section: Confronting the Complexity Of Carbon Nanotube Materials †mentioning

confidence: 99%

Confronting the complexity of CNT materials

Vargas–Lara

Douglas

2015

Soft Matter

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The morphology of commercially available carbon nanotube materials is often much more complex than the term "carbon nanotube" (CNT) would imply. Commercial CNT materials are typically composed of roughly spherical CNT domains having a highly ramified internal structure and a size on the order of microns. Clearly, such structures cannot reasonably be modeled as "rods". To address this problem, we first perform molecular dynamics simulations (MD) to generate structures similar to those measured experimentally, based on the presumptions that CNT domains are composed of worm-like cylinders having observed persistence lengths and that these CNTs are confined to spherical domains having the observed average domain size. This simple model generates structures remarkably similar to those observed experimentally. We then consider numerical path-integral computations to calculate the self-capacitance C and intrinsic conductivity [σ]∞ of these CNT rich domains. This information is then incorporated in a generalized effective medium theory to estimate the conductivity of bulk composite materials composed of these complex-shaped "particles". We term these CNT structures "tumbleweeds", given their evident morphological similarity to this naturally occurring growth form. Based on this model, we find that the conductivity percolation threshold of the tumbleweeds can be quite low, despite their quasi-spherical average shape. We also examine the structure factor S(q) of the CNT-rich domains as function of the number N of CNTs within them, to aid in the structural characterization of CNT nanocomposites. The structure factor S(q) of our model tumbleweed is found to resemble that of hyperbranched, star and dendrimer polymers, and also domain structures observed in polyelectrolytes. Commercial CNT materials at high loading should then have physical features in common with suspension of "soft" colloidal particles by virtue of their deformability and roughly spherical shape.

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“…1 SWCNT have been used for the development of nanocomposite materials, 2 molecular detection agents, 3 molecular delivery vehicles, 4 electrochemical sensors, 5,6 optical sensors, 7–11 biologically compatible nanoconjugates, 12,13 and nanotube partitioning. 14–19 Many SWCNT applications rely on their noncovalent functionalization with physisorbed polymers, such that the sp2 hybridization of the honeycomb carbon lattice of the SWCNT surface remains intact and fluorescent. Adsorbed polymers create a molecular corona around the SWCNT, which can facilitate the incorporation of SWCNT into bulk materials, 20 make SWCNT water-soluble and biocompatible, 21 appropriate for targeted delivery into organelles, 7 or enable SWCNT-based sensing.…”

Section: Introductionmentioning

confidence: 99%

Comparative Dynamics and Sequence Dependence of DNA and RNA Binding to Single Walled Carbon Nanotubes

Landry

Vuković²,

Kruss

et al. 2015

J. Phys. Chem. C

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Noncovalent polymer-single walled carbon nanotube (SWCNT) conjugates have gained recent interest due to their prevalent use as electrochemical and optical sensors, SWCNT-based therapeutics, and for SWCNT separation. However, little is known about the effects of polymer-SWCNT molecular interactions on functional properties of these conjugates. In this work, we show that SWCNT complexed with related polynucleotide polymers (DNA, RNA) have dramatically different fluorescence stability. Surprisingly, we find a difference of nearly 2500-fold in fluorescence emission between the most fluorescently stable DNA-SWCNT complex, C30 DNA-SWCNT, compared to the least fluorescently stable complex, (AT)7A-(GU)7G DNA-RNA hybrid-SWCNT. We further reveal the existence of three regimes in which SWCNT fluorescence varies nonmonotonically with SWCNT concentration. We utilize molecular dynamics simulations to elucidate the conformation and atomic details of SWCNT-corona phase interactions. Our results show that variations in polynucleotide sequence or sugar backbone can lead to large changes in the conformational stability of the polymer SWCNT corona and the SWCNT optical response. Finally, we demonstrate the effect of the coronae on the response of a recently developed dopamine nanosensor, based on (GT)15 DNA- and (GU)15 RNA-SWCNT complexes. Our results clarify several features of the sequence dependence of corona phases produced by polynucleotides adsorbed to single walled carbon nanotubes, and the implications for molecular recognition in such phases.

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High-Resolution Length Fractionation of Surfactant-Dispersed Carbon Nanotubes

Cited by 53 publications

References 35 publications

Single Nanotube Spectral Imaging To Determine Molar Concentrations of Isolated Carbon Nanotube Species

Single Nanotube Spectral Imaging To Determine Molar Concentrations of Isolated Carbon Nanotube Species

Confronting the complexity of CNT materials

Comparative Dynamics and Sequence Dependence of DNA and RNA Binding to Single Walled Carbon Nanotubes

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