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arXiv 1601.04875cond-mat.mtrl-sci
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高冲击下碳纳米卷的分子动力学研究

Carbon Nanoscrolls at High Impacts: A Molecular Dynamics Investigation

Jose Moreira de Sousa, Leonardo Dantas Machado, Cristiano Francisco Woellner, Pedro Alves da Silva Autreto, Douglas S. Galvao

摘要:

近年来,纳米结构在高应变率条件下的行为一直是人们感兴趣的对象。例如,最近的实验研究表明,在高速冲击下,碳纳米管可以解压缩,从而形成石墨烯纳米带。碳纳米卷(CNS)是尚未研究其高冲击行为的结构之一。CNS是卷成纸草状结构的石墨烯膜。它们独特的开放式拓扑结构导致了封闭式结构(如纳米管)中没有的特性。在这里,我们报告了一个完全原子反应分子动力学研究的行为CNS碰撞在高速固体目标。我们的研究结果表明,速度和滚动轴方向是关键参数,以确定所产生的形成纳米结构后的影响。涡旋开口端和基底的相对取向也非常重要。我们观察到,对于适当的速度和方向,纳米卷可以经历大的结构变形和大规模的断裂。我们还观察到展开(滚动回到平面或准平面石墨烯膜),解压缩产生纳米带,以及新化学键断裂和/或形成的显著重建。另一个有趣的结果是,如果CNS用它们的开口端冲击基底,对于一定的速度,观察到熔融的涡卷壁。

英文摘要:

The behavior of nanostructures under high strain-rate conditions has been object of interest in recent years. For instance, recent experimental investigations showed that at high velocity impacts carbon nanotubes can unzip resulting into graphene nanoribbons. Carbon nanoscrolls (CNS) are among the structures whose high impact behavior has not yet been investigated. CNS are graphene membranes rolled up into papyrus-like structures. Their unique open-ended topology leads to properties not found in close-ended structures, such as nanotubes. Here we report a fully atomistic reactive molecular dynamics study on the behavior of CNS colliding at high velocities against solid targets. Our results show that the velocity and scroll axis orientation are key parameters to determine the resulting formed nanostructures after impact. The relative orientation of the scroll open ends and the substrate is also very important. We observed that for appropriate velocities and orientations, the nanoscrolls can experience large structural deformations and large-scale fractures. We have also observed unscrolling (scrolls going back to planar or quasi-planar graphene membranes), unzip resulting into nanoribbons, and significant reconstructions from breaking and/or formation of new chemical bonds. Another interesting result was that if the CNS impact the substrate with their open ends, for certain velocities, fused scroll walls were observed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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