Buckling initiation and displacement dependence in compression of vertically aligned carbon nanotube arrays

Cao, Changhong; Reiner, Alexander P.; Chung, Chunhui; Chang, Shuquan; Kao, Imin; Kukta, R. V.; Korach, Chad S.

doi:10.1016/j.carbon.2011.03.043

Cited by 58 publications

(42 citation statements)

References 35 publications

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“…Also, for the ψ = 90% case, in order to get φ m,i < 20%, a value of i > 25 is necessary, meaning that such a low value of φ m is likely both physically and practically unattainable for A-CMNCs produced using wet infusion with a diluted (F dilut 60% by mass) phenolic resin. A possible way to achieve φ m,i < 20% at a reasonable value of i (i 10) is to apply pressure during the pyrolysis stage 28 , which will make ∆V p,1 ≡ ∆V p (the simplification in Eq 3 is no longer true), but the compressive stress will probably alter the morphology of the CNTs in the matrix 47,48 , thereby impacting the physical properties of the CNT A-CMNCs. Therefore, in order to synthesize A-CMNCs with very low porosities (φ m 20%) without changing the A-CMNC morphology, a gas phase infusion method, such as carbon vapor infiltration (CVI) 27,49-51 , would most likely be necessary.…”

Section: Resultsmentioning

confidence: 99%

Morphology and processing of aligned carbon nanotube carbon matrix nanocomposites

Stein

Wardle

2014

Carbon

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Intrinsic and scale-dependent properties of carbon nanotubes (CNTs) have led aligned CNT architectures to emerge as promising candidates for next-generation multifunctional applications. Enhanced operating regimes motivate the study of CNT-based aligned nanofiber carbon matrix nanocomposites (CNT A-CMNCs). However, in order to tailor the material properties of CNT A-CMNCs, porosity control of the carbon matrix is required. Such control is usually achieved via multiple liquid precursor infusions and pyrolyzations. Here we report a model that allows the quantitative prediction of the CNT A-CMNC density and matrix porosity as a function of number of processing steps. The experimental results indicate that the matrix porosity of A-CMNCs comprised of ∼ 1% aligned CNTs decreased from ∼ 61% to ∼ 55% after a second polymer infusion and pyrolyzation. The model predicts that diminishing returns for porosity reduction will occur after 4 processing steps (matrix porosity of ∼ 51%), and that > 10 processing steps are required for matrix porosity < 50%. Using this model, prediction of the processing necessary for the fabrication of liquid precursor derived A-CMNC architectures, with possible application to other nanowire/nanofiber systems, is enabled for a variety of high value applications.

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Section: Resultsmentioning

confidence: 99%

Morphology and processing of aligned carbon nanotube carbon matrix nanocomposites

Stein

Wardle

2014

Carbon

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“…Other differences between these nominally identical VACNT samples are the ability of some of them to recover almost completely after large compressions (Figs. S1a and c) while others deform permanently even at modest strains [7][8][9][10][11] (Figs. S1b and d).…”

Section: Compressive Behavior Of Vertically Aligned Carbon Nanotube (mentioning

confidence: 99%

Local Relative Density Modulates Failure and Strength in Vertically Aligned Carbon Nanotubes

et al. 2013

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Micromechanical experiments, image analysis, and theoretical modeling revealed that local failure events and compressive stresses of vertically aligned carbon nanotubes (VACNTs) were uniquely linked to relative density gradients. Edge detection analysis of systematically obtained scanning electron micrographs was used to quantify a microstructural figure-of-merit related to relative local density along VACNT heights. Sequential bottom-to-top buckling and hardening in stress–strain response were observed in samples with smaller relative density at the bottom. When density gradient was insubstantial or reversed, bottom regions always buckled last, and a flat stress plateau was obtained. These findings were consistent with predictions of a 2D material model based on a viscoplastic solid with plastic non-normality and a hardening–softening–hardening plastic flow relation. The hardening slope in compression generated by the model was directly related to the stiffness gradient along the sample height, and hence to the local relative density. These results demonstrate that a microstructural figure-of-merit, the effective relative density, can be used to quantify and predict the mechanical response.

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“…Furthermore Liu et al 17 have shown that agglomeration and entanglement of CNT gives rise to highly resilience property and they reported cushioning behavior of highly agglomerated carbon nanotubes. Other researchers 18,19 also shown super resilience property of agglomerated CNTs under compression. In our composite high magnification image [ fig-1(b)] clearly shows the agglomeration and entanglement of SWCNT bundles whereas low magnification image [ fig-1(c)] shows the tips of agglomerated SWCNT bundles [indicated by circles in fig 1(c)].…”

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confidence: 82%

Enhanced mechanical properties of single walled carbon nanotube-borosilicate glass composite due to cushioning effect and localized plastic flow

Ghosh

Das

et al. 2011

AIP Advances

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Buckling initiation and displacement dependence in compression of vertically aligned carbon nanotube arrays

Cited by 58 publications

References 35 publications

Morphology and processing of aligned carbon nanotube carbon matrix nanocomposites

Morphology and processing of aligned carbon nanotube carbon matrix nanocomposites

Local Relative Density Modulates Failure and Strength in Vertically Aligned Carbon Nanotubes

Enhanced mechanical properties of single walled carbon nanotube-borosilicate glass composite due to cushioning effect and localized plastic flow

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