An investigation on tensile properties of coiled carbon nanotubes using molecular dynamics simulation
Graphical abstract
Introduction
The research on the carbon nanotubes in recent years has led to widespread use of these materials in various fields such as nano-springs and biosensors [1]. Since a coiled carbon nanotube (CCNT) has a helical morphology and the extraordinary tensile properties of a straight carbon nanotube (CNT), it may present a greater potential for such applications [2], [3].
So far, the computer simulations have been carried out on CCNTs composed of only hexagonal carbon rings [4], [5], as well as, on the CCNTs containing Stone-Wales defects [6], [7], [8], [9]. It should, however, be noted that no experiments have been performed yet to identify accurately and quantitatively the existence of the Stone-Wales defects and researchers have not been able to set standards to detect them systematically [10]. Thus, it is necessary to study the mechanical behavior of the CCNTs for better understanding of their applications. Chen et al. [11] determined the spring constant and maximum strain of a double wall CCNT with tubular diameter of 126 nm. They clamped the CCNT between the two cantilevers of atomic force microscope and stretched up to 42% strain. Their results showed that CCNTs behavior is similar to an elastic spring with constant of 0.12 Nm− 1 and no plastic deformation was observed in their experiments. In another research [12], an equipped electron scanning microscope was used to study the mechanical and electrical properties of several CCNTs. The results showed that CCNT can be stretched up to strains of > 200%. Liu et al. [8] performed atomic quantum simulations on several thin CCNTs with tubular diameter and pitch length lower than 1 nm under the axial load. They reported that CCNTs show superelastic behavior and are able to withstand the strain as high as 60% in tension and 20–35% in compression. Wang et al. [7] studied the mechanical properties of CCNT using the uniaxial tensile and compression loads. The results of their simulation showed that the yield stress and yield strain of CCNT under compression are 9.2 GPa and 16%, respectively, while the yield stress and yield strain in tension are 14 GPa and 30%, respectively. Also, in their research the spring constant was calculated as 10.1 Nm− 1. In another research [6], the mechanical behavior of coiled carbon nanotubes of different diameters was investigated at different temperatures using a tensile load. The results of this research have confirmed that by increasing the temperature and decreasing the diameter of CCNTs, the tension force is decreased. Ghaderi and Haji Esmaeili [9] measured the force and fracture strain of several straight and helical nanotubes with different diameters using molecular dynamics finite element method under the tensile load. Their results exhibited that by increasing the diameter of helical nanotubes, the fracture force is increased, while the fracture strain is constant. Ju et al. [3] did the molecular dynamics simulation and tensile test on (5,5), and (10,10) single-walled carbon nanocoils, as well as, on (5,5)@(10,10) double-walled carbon nanocoils. They demonstrated that the nanocoils exhibit superelastic characteristics and a high strength similar to that of carbon nanotube of the same chirality. In a recent study [4], carbon nanosprings (CNS) without topological defects were analyzed to evaluate their spring stiffness, a three-turns CNS showed a spring constant of 0.36 N/m and maximum elongation of 38% in elastic deformation. It should, however, be noted that despite the works conducted so far, the thermodynamic equilibrium of coiled carbon nanotubes without Stone-Wales defects has rarely been investigated in the literature so further study is needed for comparison between either models for thermodynamic stability. In addition, many questions have remained yet without any answer regarding the mechanical behavior of the CCNTs. Among them, the effect of increasing the rising angle and the combined effects of temperature and rising angle on the force-displacement, stress-strain curve, and toughness of this material have not been evaluated yet. Hence, in this work, by considering the CCNTs with or without Stone-Wales, their thermodynamic stability is assessed using molecular dynamics simulation. Further, several types of CCNTs having indexes of (3,3), (4,4), and (5,5) are selected to determine their ultimate strength, elastic slope, spring constant, toughness, and fracture mechanisms.
Section snippets
Methodology
In this research, two structures of CCNTs were constructed. In the first structure, the CCNT is free from Stone-Wales defects and the carbon rings are only hexagonal. This structure is the same as that proposed in Refs. [4], [13], [14]. In the second structure, topological defects i.e. pentagonal and heptagonal carbon rings, as the Stone-Wales defects, were added to the CCNT structure. The latter structure was based on the Chuang et al. method [15]. In this model, the CCNT is derived from
Comparing the modeled structures for CCNT
The two structures constructed in the previous section, were relaxed in NPT ensemble of zero bar pressure and temperature of 300 K. The potential energy diagram versus time step and snapshots of these two structures are presented in Fig. 3, Fig. 4, respectively. As it is seen after 10,000 fs, the CCNT constructed by hexagonal carbon rings, is converted to a straight nanotube with several fractures between the carbon atomic bonds. On the other hand, the nanotube containing the Stone-Wales defects
Conclusions
The uniaxial tensile test on coiled carbon nanotubes was simulated by molecular dynamics simulation and the effect of different parameters such as temperature, tube diameter, and rising angle on the tensile behavior of these materials was investigated. The following conclusions can be derived from the results;
- 1.
Relaxation of CCNTs without Stone-Wales defects shows that these CCNTs convert to the straight CNT after a short time indicating that the existence of pentagonal and heptagonal carbon
Acknowledgements
The authors would like to thank the research boards at Sharif University of Technology, Tehran, Iran for the provision of the research facilities used in this work.
References (37)
- et al.
Electron microscopy and in situ testing of mechanical deformation of carbon nanotubes
Micron
(2011) - et al.
A molecular dynamics study of the mechanical properties of a double-walled carbon nanocoil
Comput. Mater. Sci.
(2014) - et al.
Predicting mechanical properties of carbon nanosprings based on molecular mechanics simulation
Compos. Struct.
(2014) - et al.
Structural stability of carbon nanosprings
Carbon
(2011) - et al.
Predicted mechanical properties of a coiled carbon nanotube
Carbon
(2012) - et al.
Nonlinear analysis of coiled carbon nanotubes using the molecular dynamics finite element method
Mater. Sci. Eng. A
(2013) - et al.
Evaluating the characteristics of multiwall carbon nanotubes
Carbon
(2011) - et al.
Mechanical and electrical properties of carbon tubule nanocoils
Phys. B Condens. Matter
(2002) - et al.
On the structural rules of helically coiled carbon nanotubes
J. Mol. Struct.
(2012) - et al.
Continuum interpretation of virial stress in molecular simulations
Int. J. Solids Struct.
(2008)
Molecular dynamic simulations on tensile mechanical properties of single-walled carbon nanotubes with and without hydrogen storage
Comput. Mater. Sci.
Simulation of the elastic response and the buckling modes of single-walled carbon nanotubes
Comput. Mater. Sci.
Helical carbon nanotubes: intrinsic peroxidase catalytic activity and its application for biocatalysis and biosensing
Chem. Eur. J.
Giant stretchability and reversibility of tightly wound helical carbon nanotubes
J. Am. Chem. Soc.
Superelasticity of carbon nanocoils from atomistic quantum simulations
Nanoscale Res. Lett.
Mechanics of a carbon nanocoil
Nano Lett.
Electronic band structure of coiled carbon nanotubes
Acta Phys. Pol. A
Structure and stability of coiled carbon nanotubes
Phys. Status Solidi B
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