Electronic and Mechanical Properties of Carbon Nanotubes

Forró, Lászlø; Salvetat, Jean‐Paul; Bonard, Jean–Marc; Bacsa, Revathi; Thomson, Neil H.; Garaj, Slaven; Thiên-Nga, L.; Gáal, R.; Kulik, Andrzej; Ruzicka, Barbara; Degiorgi, L.; Bachtold, Adrian; Schönenberger, Christian; Pekker, S.; Hernádi, Klára

doi:10.1007/0-306-47098-5_22

Cited by 24 publications

(13 citation statements)

References 39 publications

(49 reference statements)

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“…1 Variation in helicity and diameter of these SWNTs, represented as chirality, can induce significant changes in their electrokinetic surface properties. 2 Change in SWNT chirality results in electron confinement differences, which causes electron transport variation along the SWNT axes and thus exhibits unique physicochemical, electronic, and optical properties.…”

Section: Introductionmentioning

confidence: 99%

Chirality Affects Aggregation Kinetics of Single-Walled Carbon Nanotubes

Khan

Afrooz

Flora

et al. 2013

Environ. Sci. Technol.

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Aggregation kinetics of chiral-specific semiconducting single-walled carbon nanotubes (SWNTs) was systematically studied through time-resolved dynamic light scattering. Varied monovalent (NaCl) and divalent (CaCl2) electrolyte composition was used as background solution chemistry. Suwannee River humic acid (SRHA) was used to study the effects of natural organic matter on chirally separated SWNT aggregation. Increasing salt concentration and introduction of divalent cations caused aggregation of SWNT clusters by suppressing the electrostatic repulsive interaction from the oxidized surfaces. The (6,5) SWNTs, i.e., SG65, with relatively lower diameter tubes compared to (7,6), i.e., SG76, showed substantially higher stability (7- and 5-fold for NaCl and CaCl2, respectively). The critical coagulation concentration (CCC) values were 96 and 13 mM NaCl in the case of NaCl and 2.8 and 0.6 mM CaCl2 for SG65 and SG76, respectively. The increased tube diameter for (7,6) armchair SWNTs likely presented with higher van der Waals interaction and thus increased the aggregation propensity substantially. The presence of SRHA enhanced SWNT stability in divalent CaCl2 environment through steric interaction from adsorbed humic molecules; however showed little or no effects for monovalent NaCl. The mechanism of aggregation—describing favorable interaction tendencies for (7,6) SWNTs—is probed through ab initio molecular modeling. The results suggest that SWNT stability can be chirality dependent in typical aquatic environment.

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Section: Introductionmentioning

confidence: 99%

Chirality Affects Aggregation Kinetics of Single-Walled Carbon Nanotubes

Khan

Afrooz

Flora

et al. 2013

Environ. Sci. Technol.

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“…Single-walled carbon nanotubes (SWNTs), tubular structures of sp 3 hybridized carbon atoms, provide unique electrical, mechanical, and optical properties (Iijima and Ichihashi, 1993; Forro et al 2000; Baughman et al, 2002; Xia et al, 2003). Variations of tube diameter and atomic arrangement of carbon, together known as chirality, introduce added advantages to these helicoids and thus widen the application premise to drug delivery, therapeutics, and electronics (Thostenson et al, 2001; Bachilo et al, 2002; Minot et al, 2003; Chen et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Fractal structures of single-walled carbon nanotubes in biologically relevant conditions: Role of chirality vs. media conditions

et al. 2013

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Aggregate structure of covalently functionalized chiral specific semiconducting single-walled carbon nanotubes (SWNTs) was systematically studied employing static light scattering (SLS). Fractal dimensions (Df) of two specific chirality SWNTs—SG65 and SG76 with (6, 5) and (7, 6) chiral enrichments—were measured under four biological exposure media conditions, namely: Dulbecco’s Modified Eagle Medium (DMEM), Minimum Essential Medium (MEM), Roswell Park Memorial Institute (RPMI) 1640 medium, and 0.9% saline solution. The SWNTs exhibited chiral dependence on Df with SG65 showing more fractal or loosely bound aggregate structures, i.e., lower Df values (range of 2.24 ± 0.03 to 2.64 ± 0.05), compared to the SG76 sample (range of 2.58 ± 0.13 to 2.90 ± 0.08). All the Df values reported are highly reproducible, measured from multiple SLS runs and estimated with ‘random block-effects’ statistical analysis that yielded all p values to be <0.001. The key mechanism for such difference in Df between the SWNT samples was identified as the difference in van der Waals (VDW) interaction energies of these samples, where higher VDW of SG76 resulted in tighter packing density. Effect of medium type showed lower sensitivity; however, presence of di-valent cations (Ca2+) in DMEM and MEM media resulted in relatively loose or more fractal aggregates. Moreover, presence of fetal bovine serum (FBS) and bovine serum albumin (BSA), used to mimic the in vitro cell culture condition, reduced the Df values, i.e., created more fractal structures. Steric hindrance to aggregation was identified as the key mechanism for creating the fractal structures. Also, increase in FBS concentration from 1% to 10% resulted in increasingly lower Df values.

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“…For different experimental measurement techniques, the values of Young's modulus vary in the range of 1.22 TPa-1.26 TPa depending on the size and chirality of the SWNTs (Dresselhaus et al 2001). Primarily, the moduli of MWNTs are correlated to the amount of disorder in the nanotube walls (Forro et al 2002). Primarily, the moduli of MWNTs are correlated to the amount of disorder in the nanotube walls (Forro et al 2002).…”

Section: Strength and Elasticitymentioning

confidence: 99%