Abstract
This article presents the results of a computer study of electrical conductivity and deformation behavior of new graphene–carbon nanotube (CNT) composite films under bending and stretching. Mono- and bilayer hybrid structures with CNTs (10,0) and (12,0) and an inter-tube distance of 10 and 12 hexagons were considered. It is revealed that elastic deformation is characteristic for mono- and bilayer composite films both in bending and stretching. It is found that, in the case of bending in a direction perpendicular to CNTs, the composite film takes the form of an arc, and, in the case of bending in a direction along CNTs, the composite film exhibits behavior that is characteristic of a beam subjected to bending deformation as a result of exposure to vertical force at its free end. It is shown that mono- and bilayer composite films are more resistant to axial stretching in the direction perpendicular to CNTs. The bilayer composite films with an inter-tube distance of 12 hexagons demonstrate the greatest resistance to stretching in a direction perpendicular to CNTs. It is established that the CNT diameter and the inter-tube distance significantly affect the strength limits of composite films under axial stretching in a direction along CNTs. The composite films with CNT (10,0) and an inter-tube distance of 12 hexagons exhibit the highest resistance to stretching in a direction along CNTs. The calculated distribution of local stresses of the atomic network of deformed mono- and bilayer composite films showed that the maximum stresses fall on atoms forming covalent bonds between graphene and CNT, regardless of the CNT diameter and inter-tube distance. The destruction of covalent bonds occurs at the stress of ~1.8 GPa. It is revealed that the electrical resistance of mono- and bilayer composite films decreases with increasing bending. At the same time, the electrical resistance of a bilayer film is 1.5–2 times less than that of a monolayer film. The lowest electrical resistance is observed for composite films with a CNT (12,0) of metallic conductivity.
Highlights
At present, a new scientific direction devoted to the theoretical and experimental study of hybrid materials based on two-dimensional (2D) graphene and one-dimensional (1D) carbon nanotubes (CNTs) exists in materials science [1,2,3,4,5,6]
As a result of a series of numerical experiments carried out using the molecular dynamics method and the SCC-DFTB method, we determined patterns of the deformation behavior and electrical conductivity of mono- and bilayer graphene–CNT composite films with CNTs (12,0) and (10,0) and inter-tube distances of 10 and 12 hexagons under stretching and bending
It was established that the direction of deformation plays an important role in determining the deformation behavior of the graphene–CNT structure under bending
Summary
A new scientific direction devoted to the theoretical and experimental study of hybrid materials based on two-dimensional (2D) graphene and one-dimensional (1D) carbon nanotubes (CNTs) exists in materials science [1,2,3,4,5,6]. The reason for the increased attention of scientists to these hybrid structures is their unusually wide range of applications and an improved palette of properties as compared to conventional carbon materials due to the synergistic effect of CNTs and graphene. The first results of a study of novel carbon composite structures showed their superiority over individual nanotubes and graphene in electrical, optical, and electrochemical properties, providing new ways for developing promising practical applications based on these materials. The excellent electrochemical properties of pillared graphene led to its wide application as an electrode for batteries and supercapacitors [8,9,10,11]
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