Qin Xinmao, Yan Wanjun, Guo Xiaotian, Gao Tinghong
School of Electronic and Information Engineering, Anshun University Anshun 561000 China
School of Mathematics and Physics, Anshun University Anshun 561000 China.
RSC Adv. 2018 May 9;8(31):17034-17043. doi: 10.1039/c8ra02415d.
Molecular dynamics simulations with adaptive intermolecular reactive empirical bond order (AIREBO) potential are performed to investigate the effects of rectangular nanoholes with different areas, aspect ratios (length/width ratios) and orientations on the tensile strength of defective graphene. The simulations reveal that variation of area, aspect ratio and orientation of rectangular nanohole can significantly affect the tensile strength of defective graphene. For example, defective graphene with a larger area of rectangular nanohole shows a bigger drop in tensile strength. It was found that the tensile strength of both armchair and zigzag edged graphene monotonically decreases with area increases in rectangular nanohole. Changes in aspect ratio and orientation of rectangular nanohole, however, can either decrease or increase the tensile strength of defective graphene, dependent on the tensile direction. This study also presents information that the tensile strength of defective graphene with large area of nanohole is more sensitive to changes in aspect ratio and orientation than is defective graphene with small area of nanohole. Interestingly, variation of tensile strength of defective graphene from MD simulations is in good agreement with predictions from energy-based quantized fracture mechanics (QFM). The present results suggest that the effect of nanoholes on the tensile strength of graphene provides essential information for predictive optimization of mechanical properties and controllable structural modification of graphene through defect engineering.
采用具有自适应分子间反应经验键级(AIREBO)势的分子动力学模拟,研究不同面积、纵横比(长/宽比)和取向的矩形纳米孔对缺陷石墨烯拉伸强度的影响。模拟结果表明,矩形纳米孔的面积、纵横比和取向变化会显著影响缺陷石墨烯的拉伸强度。例如,矩形纳米孔面积较大的缺陷石墨烯的拉伸强度下降幅度更大。研究发现,扶手椅型和锯齿型边缘石墨烯的拉伸强度均随矩形纳米孔面积的增加而单调降低。然而,矩形纳米孔纵横比和取向的变化,取决于拉伸方向,可能会降低或增加缺陷石墨烯的拉伸强度。本研究还表明,纳米孔面积较大的缺陷石墨烯的拉伸强度对纵横比和取向变化的敏感度高于纳米孔面积较小的缺陷石墨烯。有趣的是,分子动力学模拟得到的缺陷石墨烯拉伸强度变化与基于能量的量子断裂力学(QFM)预测结果吻合良好。目前的结果表明,纳米孔对石墨烯拉伸强度的影响为通过缺陷工程对石墨烯力学性能进行预测优化和可控结构改性提供了重要信息。