Impacts of environments on nanoscale wear behavior of graphene: Edge passivation vs. substrate pinning
Impacts of environments on nanoscale wear behavior of graphene: Edge passivation vs. substrate pinning
复制标题
环境对石墨烯纳米级磨损行为的影响：边缘钝化与基底钉扎
DOI：
10.1016/j.carbon.2018.06.029
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发表时间：
2018-11-01
期刊：
影响因子：
10.9
通讯作者：
Li, Qunyang
中科院分区：
文献类型：
--
作者：
Qi, Yizhou;Liu, Jun;Li, Qunyang
石墨烯是一种典型的二维层状结构材料，具有很高的潜力作为一种有效的和原子级薄的固体润滑剂。然而，石墨烯优异的润滑性能被发现受到环境湿度的严重影响，表现出复杂的，有时是矛盾的趋势。在这项工作中，石墨烯的抗磨损性能进行了探索，通过纳米划痕试验在不同的湿度。实验结果表明，石墨烯的磨损主要发生在悬挂键最丰富的台阶边缘。一般来说，潮湿的环境会提高石墨烯的耐磨性，这是由于悬挂键被冷凝水钝化，如分子动力学模拟所证实的。然而，对于可以与石墨烯边缘处的碳原子强烈相互作用的衬底表面，由于衬底钉扎效应，可以观察到显著改善的抗磨损性能，较少依赖于湿度。所揭示的机制成功地阐明了湿度依赖性的各种基板上的石墨烯的磨损特性。这些发现还为改善石墨烯在广泛的机械应用中的性能提供了一般策略。(C)2018爱思唯尔有限公司版权所有
Being a typical layer structured two-dimensional material, graphene has a high potential as an efficient and atomically-thin solid lubricant. However, the outstanding lubricating property of graphene is found to be seriously impacted by environmental humidity, exhibiting a complicated and sometimes contradicting trend. In this work, the anti-wear performance of graphene was explored by nanoscale scratch tests under different humidities. The experimental results show that wear of graphene primarily occurs at the step edge where dangling bonds are most abundant. In general, humid environment would improve wear resistance of graphene due to dangling bond passivation by condensed water, as confirmed by molecular dynamics simulations. However, for substrate surfaces that can strongly interact with the carbon atoms at the graphene edge, a noticeably improved anti-wear performance, less dependent on humidity, can be observed due to substrate pinning effect. The revealed mechanisms successfully clarify humidity dependence of wear characteristics of graphene on various substrates. The findings also provide a general strategy for improving the performance of graphene in a broad range of mechanical applications. (C) 2018 Elsevier Ltd. All rights reserved.