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Water filling and electric field-induced enhancement in the mechanical property of carbon nanotubes.

Ye HF, Zheng YG, Zhang ZQ, Chen Z, Zhang HW - Sci Rep (2015)

Bottom Line: The effects of water filling and electric field on the mechanical property of carbon nanotubes (CNTs) are investigated with molecular dynamics simulations.The simulation results indicate that the water filling and electric field could enhance the elastic modulus but reduce the Poisson's ratio of the CNTs.The present findings provide a valuable route for the optimized design and application of the nanoscale functional devices based on the water-filled CNTs.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024, P. R. China.

ABSTRACT
The effects of water filling and electric field on the mechanical property of carbon nanotubes (CNTs) are investigated with molecular dynamics simulations. The simulation results indicate that the water filling and electric field could enhance the elastic modulus but reduce the Poisson's ratio of the CNTs. As for the buckling behaviors, a significant enhancement could be observed in the yield stress and average post-buckling stress of the CNTs. In particular, the enhancement in the yield stress induced by the water filling and electric field could be even higher than that resulted from the solid filling. Moreover, a transition mechanism from the rod instability to shell buckling is shown to explain the nonmonotonic variation of yield stress, and the critical diameter can be tuned through filling the water molecules and applying the electric field. The present findings provide a valuable route for the optimized design and application of the nanoscale functional devices based on the water-filled CNTs.

No MeSH data available.


Related in: MedlinePlus

The yield stresses of the CNTs in the three cases under the compressive load.The insets illustrate the three representative configuration evolutions of the (8, 8) and (10, 10) CNTs in the initial buckling stage. The color on the wall of the CNTs represents the distribution of the strain energy (eV).
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f4: The yield stresses of the CNTs in the three cases under the compressive load.The insets illustrate the three representative configuration evolutions of the (8, 8) and (10, 10) CNTs in the initial buckling stage. The color on the wall of the CNTs represents the distribution of the strain energy (eV).

Mentions: The yield stresses of the three types of the CNTs as a function of the diameter are plotted in Fig. 4. The yield stress reflects the critical value for the CNTs from the elastic to buckling deformations. For the empty CNTs (square samples), the yield stress has an increase for the (8, 8) CNT relative to the (6, 6) CNT, and then it decreases with the increase in the diameter. The nonmonotonic variation can be attributed to the different buckling mechanisms of the CNTs with different slenderness ratios. Though the final buckling modes of all the CNTs could be seen as the global instability, the initial buckling types, at which the stress just exceeds the yield stress, are completely different. The initial buckling mode of the small-diameter CNTs (the (6, 6) and (8, 8) CNTs) are the rod-like global buckling, as shown in the left two insets of Fig. 4. In the continuum theory, the yield stress in this case is in proportion to the square of diameter, i.e., , in which E is the elastic modulus, and D and L are the diameter and length of the CNTs2225. As for the CNTs with larger diameter, the local buckling appears symmetrically and persists for several picoseconds, which is similar to the shell buckling, as shown in the lower two insets of Fig. 4. Based on the shell theory, the yield stress is in inverse proportion to the diameter and can be expressed as , in which t and ν are the thickness and Poisson’s ratio of the CNTs2225. Based on the two equations as given above, a nonmonotonic trend of the yield stress can be obtained after identifying a transition diameter from the rod buckling to the shell buckling. As a result, the physics behind the present simulation results could be qualitatively explained although the average difference between the simulation results and the predictions from the continuum theory is about 20%. The turning point in the yield stress-diameter curve of the empty CNTs indicates that the transition diameter is in the range of 10.85 ~ 13.56 Å.


Water filling and electric field-induced enhancement in the mechanical property of carbon nanotubes.

Ye HF, Zheng YG, Zhang ZQ, Chen Z, Zhang HW - Sci Rep (2015)

The yield stresses of the CNTs in the three cases under the compressive load.The insets illustrate the three representative configuration evolutions of the (8, 8) and (10, 10) CNTs in the initial buckling stage. The color on the wall of the CNTs represents the distribution of the strain energy (eV).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664918&req=5

f4: The yield stresses of the CNTs in the three cases under the compressive load.The insets illustrate the three representative configuration evolutions of the (8, 8) and (10, 10) CNTs in the initial buckling stage. The color on the wall of the CNTs represents the distribution of the strain energy (eV).
Mentions: The yield stresses of the three types of the CNTs as a function of the diameter are plotted in Fig. 4. The yield stress reflects the critical value for the CNTs from the elastic to buckling deformations. For the empty CNTs (square samples), the yield stress has an increase for the (8, 8) CNT relative to the (6, 6) CNT, and then it decreases with the increase in the diameter. The nonmonotonic variation can be attributed to the different buckling mechanisms of the CNTs with different slenderness ratios. Though the final buckling modes of all the CNTs could be seen as the global instability, the initial buckling types, at which the stress just exceeds the yield stress, are completely different. The initial buckling mode of the small-diameter CNTs (the (6, 6) and (8, 8) CNTs) are the rod-like global buckling, as shown in the left two insets of Fig. 4. In the continuum theory, the yield stress in this case is in proportion to the square of diameter, i.e., , in which E is the elastic modulus, and D and L are the diameter and length of the CNTs2225. As for the CNTs with larger diameter, the local buckling appears symmetrically and persists for several picoseconds, which is similar to the shell buckling, as shown in the lower two insets of Fig. 4. Based on the shell theory, the yield stress is in inverse proportion to the diameter and can be expressed as , in which t and ν are the thickness and Poisson’s ratio of the CNTs2225. Based on the two equations as given above, a nonmonotonic trend of the yield stress can be obtained after identifying a transition diameter from the rod buckling to the shell buckling. As a result, the physics behind the present simulation results could be qualitatively explained although the average difference between the simulation results and the predictions from the continuum theory is about 20%. The turning point in the yield stress-diameter curve of the empty CNTs indicates that the transition diameter is in the range of 10.85 ~ 13.56 Å.

Bottom Line: The effects of water filling and electric field on the mechanical property of carbon nanotubes (CNTs) are investigated with molecular dynamics simulations.The simulation results indicate that the water filling and electric field could enhance the elastic modulus but reduce the Poisson's ratio of the CNTs.The present findings provide a valuable route for the optimized design and application of the nanoscale functional devices based on the water-filled CNTs.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024, P. R. China.

ABSTRACT
The effects of water filling and electric field on the mechanical property of carbon nanotubes (CNTs) are investigated with molecular dynamics simulations. The simulation results indicate that the water filling and electric field could enhance the elastic modulus but reduce the Poisson's ratio of the CNTs. As for the buckling behaviors, a significant enhancement could be observed in the yield stress and average post-buckling stress of the CNTs. In particular, the enhancement in the yield stress induced by the water filling and electric field could be even higher than that resulted from the solid filling. Moreover, a transition mechanism from the rod instability to shell buckling is shown to explain the nonmonotonic variation of yield stress, and the critical diameter can be tuned through filling the water molecules and applying the electric field. The present findings provide a valuable route for the optimized design and application of the nanoscale functional devices based on the water-filled CNTs.

No MeSH data available.


Related in: MedlinePlus