[2+1] Additions of (n,0)(n=6−10) single-walled carbon nanotubes with di-vacancies based on defect curvature: A first-principles study

2019 ◽  
Vol 18 (01) ◽  
pp. 1950004
Author(s):  
Lei Li ◽  
Hongwei Fan ◽  
Hezhuan Wei ◽  
Shengli An ◽  
Guixiao Jia

Binding energies ([Formula: see text], geometric and electronic structures for [[Formula: see text]](O/[[Formula: see text]]) additions of O atom on ([Formula: see text])([Formula: see text] − 10) single-walled carbon nanotubes with di-vacancies are studied using a GGA-PBE method, and defect curvature ([Formula: see text]) is used to predict reactivities of different C—C bonds at defect area. Calculated results show that the C—C bonds can be divided into two types: broken C—C bonds corresponding to adducts with a C—O—C configuration structure and unbroken C—C bonds corresponding to adducts with a closed-3MR structure. [Formula: see text] of O/[[Formula: see text]] additions for the adduct with the C—O—C configuration structure monotonously increases with the increase of [Formula: see text] in any ([Formula: see text],0)([Formula: see text]) tube and decreases with the increase of [Formula: see text] in ([Formula: see text],0)([Formula: see text], 7, 10) tubes. Besides the fact that [Formula: see text] value is mainly determined by the defect curvature, it is also affected by band gaps, bonding characteristic of C—C bonds in the highest occupied molecular orbital (HOMO) and geometric structures. The study would provide a theoretical basis for surface modifications of carbon nanotubes with atomic vacancy defects.

2016 ◽  
Vol 30 (08) ◽  
pp. 1650118 ◽  
Author(s):  
Igor K. Petrushenko ◽  
Konstantin B. Petrushenko

The structural and elastic properties of neutral and ionized dichlorocarbene (CCl2) functionalized single-walled carbon nanotubes (SWCNTs) were studied using density functional theory (DFT). The Young’s modulus of ionized pristine SWCNTs is found to decrease in comparison to that of neutral models. The interesting effect of increase in Young’s modulus values of ionized functionalized SWCNTs is observed. We ascribe this feature to the concurrent processes of the bond elongation on ionization and the local deformation on cycloaddition. The strong dependence of the elasticity modulus on the number of addends is also observed. However, the CCl2-attached SWCNTs in their neutral and ionized forms remain strong enough to be suitable for the reinforcement of composites. In contrast to the elastic properties, the binding energies do not change significantly, irrespective of CCl2 coverage.


2009 ◽  
Vol 6 (s1) ◽  
pp. S147-S152 ◽  
Author(s):  
Navaratnarajah Kuganathan

The structure and binding energies of antimony selenide crystals encapsulated within single-walled carbon nanotubes are studied using density functional theory. Calculations were performed on the simulated Sb2Se3structure encapsulated within single walled nanotube to investigate the perturbations on the Sb2Se3crystal and tube structure and electronic structure and to estimate the binding energy. The calculated structures are in good agreement with the experimental high resolution transmission electron microscopy images of the Sb2Se3@SWNT. The calculated binding energy shows that larger diameter tube could accommodate the Sb2Se3crystals exothermically. Minimal charge transfer is observed between nanotube and the Sb2Se3crystals.


Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4812
Author(s):  
Nii Amah Dagadu ◽  
Shahram Ajori ◽  
Yaw Delali Bensah ◽  
Kwabena Kan-Dapaah ◽  
Stephen Kofi Armah ◽  
...  

This study is meant to address the understanding of the interactions between poly para-phenylene vinylene (PPV) oligomers, graphene and single-walled carbon nanotubes (SWCNT). To this end, the binding energies of the PPV oligomers with graphene and SWCNTs were investigated. Calculations are performed and the parameters related to van der Waal vdW interactions are discussed to achieve and confirm the crystallization of oligomers of PPV into herringbone (HB) structure arrangement, which is known to be the most stable conformation at 300 K. Finally, the interfacial interactions between crystal PPV, graphene and SWCNT are carried out. According to the results, the intramolecular potential energies of PPV chains are found to increase linearly with each extending PPV monomer unit by approximately 50 kcal/mol. Moreover, the interfacial interaction properties analysis using radial distribution functions (RDFs) for PPV-graphene and PPV-SWCNT show significant disordering of the arrangement of molecules, which is more pronounced for PPV-SWCNT than that in PPV-graphene. The radius of gyration (Rg) profiles show a net decrease of ∼−0.8, for PPV-graphene with different surface coverage, and, a net increase of ∼+0.6, for PPV-SWCNT; meaning that, the binding between PPV-graphene is much stronger than with PPV-SWCNT.


2010 ◽  
Vol 97-101 ◽  
pp. 3749-3752
Author(s):  
Li Jie Chen ◽  
Qi Zhao ◽  
Zun Qun Gong

In this paper, based on the continuum mechanics method, we adopt the three-dimensional finite element (FE) models to study the effects of different defects on buckling behavior of armchair and zigzag single-walled carbon nanotubes (SWCNTs) under axial compression. The variations of the buckling modes and the critical buckling strains with the diameter and the length-diameter ratio of SWCNTs are investigated. The diameters of SWCNTs vary from about 0.2 to 2 nm, and the length-diameter ratios vary from 3 to 30. Two kinds of atom vacancy defects are considered. The calculation results show that the length and the diameter of SWCNTs are relatively significant factors affecting the buckling behavior of SWCNTs. There is an optimal diameter with which the SWCNTs can bear much higher axial compression load than those with other diameters. The defects affect the buckling behavior of SWCNTs obviously when the length-diameter ratio of the nanotube is about less than 8 and the defects studied in this paper can decrease the critical buckling strain by a largest proportion of 41.5%.


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