Mesoscopic computational model of covalent cross-links and mechanisms of load transfer in cross-linked carbon nanotube films with continuous networks of bundles

Volkov, Alexey N.; Banna, Abu Horaira

doi:10.1016/j.commatsci.2019.109410

Cited by 5 publications

(30 citation statements)

References 98 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results for the pullout test are intrinsically dependent on the bundle length, even if the periodic boundary conditions are used. 74 Our MD simulations are performed for the bundle length of L T = 59.6 Å used in ref 57 to make our results comparable with those obtained in that work. All simulations are performed at n 0 = n 1 and for the linear CL densities varying from 0.5 nm −1 to 20 nm −1 .…”

Section: ■ Model and Methodssupporting

confidence: 63%

“…For in silico generation of CNT films with random continuous networks of nanotubes and simulations of mechanical loading of such films, we use a coarse-grained mesoscopic model, which was initially proposed in ref 14 and recently extended to study the mechanical properties of CNT materials with covalent CLs between nanotubes. 74 In this model, each nanotube is represented by a chain of stretchable cylindrical mesoscopic elements or segments, where each segment consists of multiple carbon atoms. The position of nanotube k in a material sample composed of N T CNTs is defined by nodes with the position vectors r (k)i (i = 1, .., N k , where N k is the number of nodes in CNT k).…”

Section: ■ Model and Methodsmentioning

confidence: 99%

“…79 In the present work, the mesoscopic force field accounts for elastic stretching and bending of nanotubes, 14 nonbonded van der Waals intertube interaction, 75 and covalent CLs between nanotubes. 74 The total potential energy U of the simulated system during its mechanical loading is equal to…”

Section: ■ Model and Methodsmentioning

confidence: 99%

“…The tubular potential method ensures the absence of corrugation of the intertube potential for curved nanotubes, eliminates artificial intertube friction, and is capable of describing the self-assembly of nanotubes into continuous networks of entangled bundles. 66,72,74 The CL energy is defined assuming that each CL in an in-silico-generated material sample represents an individual CL in the real material. Then,…”

Section: ■ Model and Methodsmentioning

confidence: 99%

“…The sketches illustrating the definitions of all geometrical parameters in eqs A2 and A3 can be found in ref 74 and section S1 in the Supporting Information.…”

Section: Cross-links and Its Parametrizationmentioning

confidence: 99%

See 4 more Smart Citations

Chirality-Dependent Mechanical Properties of Bundles and Thin Films Composed of Covalently Cross-Linked Carbon Nanotubes

2022

Self Cite

View full text Add to dashboard Cite

The effect of nanotube chirality on the mechanical properties of materials composed of single-walled carbon nanotubes (CNTs) is poorly understood since the interfacial load transfer in such materials is strongly dependent on the intertube interaction and structure of the nanotube network. Here, a combined atomistic-mesoscopic study is performed to reveal the effect of CNT diameter on the deformation mechanisms and mechanical properties of CNT bundles and low-density CNT films with covalent cross-links (CLs). First, the pullout of the central nanotube from bundles composed of seven (5,5), (10,10), (20,20), (17,0), and (26,0) CNTs is studied in molecular dynamics simulations based on the ReaxFF force field. The simulations show that the shear modulus and strength increase with decreasing CNT diameter. The results of atomistic simulations are used to parametrize a mesoscopic model of CLs and to perform mesoscopic simulations of in-plane tension and compression of thin films composed of thousands of cross-linked CNTs. The mechanical properties of CNT films are found to be strongly dependent on CNT diameter. The film modulus increases as the CNT diameter increases, while the tensile strength decreases. The in-plane compression is characterized by collective bending of whole films and order-of-magnitude smaller compressive strengths. The films composed of (5,5) CNTs exhibit the ability for large-strain compression without irreversible changes in the material structure. The stretching rigidity of individual nanotubes and volumetric CL density are identified as the key factors that dominate the effect of CNT chirality on the mechanical properties of CNT films. The film modulus is affected by both CL density and stretching rigidity of CNTs, while the tensile strength is dominated by CL density. The obtained results suggest that the on-demand optimization of the mechanical properties of CNT films can be performed by tuning the nanotube chirality distribution.

show abstract

Section: ■ Model and Methodssupporting

confidence: 63%

Section: ■ Model and Methodsmentioning

confidence: 99%

Section: ■ Model and Methodsmentioning

confidence: 99%

Section: ■ Model and Methodsmentioning

confidence: 99%

“…The sketches illustrating the definitions of all geometrical parameters in eqs A2 and A3 can be found in ref 74 and section S1 in the Supporting Information.…”

Section: Cross-links and Its Parametrizationmentioning

confidence: 99%

See 3 more Smart Citations

Chirality-Dependent Mechanical Properties of Bundles and Thin Films Composed of Covalently Cross-Linked Carbon Nanotubes

2022

Self Cite

View full text Add to dashboard Cite

show abstract

Revealing Density Thresholds of Carbon Nanotube Cross-Links for Load Transfer: A Graph Theory Strategy

Wang

Zhu

et al. 2022

ACS Nano

View full text Add to dashboard Cite

We report that the load transfer in carbon nanotube (CNT) networks is determined by the cross-link density via three critical thresholds, namely, percolation, connection, and saturation, which divide the transfer into four different modes. Reminiscent of the connectivity problem in the graph theory, an individual path for the successive load transfer through the network is formed at the first threshold, then all CNTs are connected together by cross-links at the second one, and finally, the connections are gradually converted into tetrahedrons toward a rigidized connectivity until the third saturation threshold. The power–law distribution of the number of cross-links per CNT shows a preferential linking mechanism, i.e., that the CNTs with high cross-links are more attractive to form new cross-links than the CNTs with low cross-links, while repetitive cross-links could hardly improve the strength of CNT networks.

show abstract

Effects of the nanotube length and network morphology on the deformation mechanisms and mechanical properties of cross-linked carbon nanotube films

Banna

Kayang

Volkov

2021

Journal of Applied Physics

View full text Add to dashboard Cite

The effects of the carbon nanotube (CNT) length and material structure on the mechanical properties of free-standing thin CNT films with continuous networks of bundles of nanotubes and covalent cross-links are studied in large-scale simulations. The simulations are performed based on a dynamic mesoscopic model that accounts for stretching and bending of CNTs, van der Waals interaction between nanotubes, and inter-tube cross-links. It is found that the tensile modulus and strength of the CNT films strongly increase with increasing CNT length, but the effect of the nanotube length is altered by the cross-link density. The mutual effect of the nanotube length and cross-link density on the modulus and strength is primarily determined by a single parameter that is equal to the average number of cross-links per nanotube. The modulus and strength, as functions of this parameter, follow the power-type scaling laws with strongly different exponents. The film elongation at the maximum stress is dominated by the value of the cross-link density. The dispersion of nanotubes without formation of thick bundles results in a few-fold increase in the modulus and strength. The variation of the film properties is explained by the effects of the CNT length, cross-link density, and network morphology on the network connectivity. The in-plane compression results in the collective bending of nanotubes and folding of the whole film with only minor irreversible changes in the film structure. Depending on the CNT length, the reliefs of the folded films vary from a complex two-dimensional landscape to a quasi-one-dimensional wavy surface.

show abstract

Mesoscopic computational model of covalent cross-links and mechanisms of load transfer in cross-linked carbon nanotube films with continuous networks of bundles

Cited by 5 publications

References 98 publications

Chirality-Dependent Mechanical Properties of Bundles and Thin Films Composed of Covalently Cross-Linked Carbon Nanotubes

Chirality-Dependent Mechanical Properties of Bundles and Thin Films Composed of Covalently Cross-Linked Carbon Nanotubes

Revealing Density Thresholds of Carbon Nanotube Cross-Links for Load Transfer: A Graph Theory Strategy

Effects of the nanotube length and network morphology on the deformation mechanisms and mechanical properties of cross-linked carbon nanotube films

Contact Info

Product

Resources

About