Mechanical properties of carbon nanotubes with vacancies and related defects
Mechanical properties of carbon nanotubes with vacancies and related defects
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DOI：
10.1103/physrevb.70.245416
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发表时间：
2004-12-01
影响因子：
3.7
通讯作者：
Kaski, K
中科院分区：
文献类型：
--
作者：
Sammalkorpi, M;Krasheninnikov, A;Kaski, K
虽然生长态碳纳米管具有相对较少的缺陷，但缺陷可能出现在纯化阶段，或者在针对所需功能性时通过高能粒子照射或通过化学处理故意引入。缺陷，特别是空位，也会引起一种有害的影响--纳米管轴向力学性能的恶化。通过采用分子动力学模拟和连续介质理论，我们研究的杨氏模量和拉伸强度的纳米管与空位相关的缺陷依赖于缺陷和缺陷特性的浓度。我们推导出一个解析表达式，与原子计算机模拟参数化的系数，它涉及的杨氏模量和碳纳米管中的缺陷密度。我们进一步表明，单壁纳米管的拉伸强度和临界应变下降了近2倍，如果一个未重构的空位存在。然而，这种机械特性的恶化部分地被纳米管通过饱和悬挂键来修复原子网络中的空位的能力所缓解。
Although as-grown carbon nanotubes have relatively few defects, defects can appear at the purification stage or be deliberately introduced by irradiation with energetic particles or by chemical treatment when aiming at the desired functionality. The defects, especially vacancies, give also rise to a deleterious effect-deterioration of axial mechanical properties of nanotubes. By employing molecular dynamics simulations and continuum theory we study how the Young's modulus and tensile strength of nanotubes with vacancy-related defects depend on the concentration of defects and defect characteristics. We derive an analytical expression, with coefficients parametrized from atomistic computer simulations, which relates the Young's modulus and defect density in carbon nanotubes. We further show that the tensile strength and critical strain of single-walled nanotubes decrease by nearly a factor of 2 if an unreconstructed vacancy is present. However, this deterioration in the mechanical characteristics is partly alleviated by the ability of nanotubes to heal vacancies in the atomic network by saturating dangling bonds.