Investigation of mechanical properties and structural integrity of graphene aerogels via molecular dynamics simulations
Investigation of mechanical properties and structural integrity of graphene aerogels via molecular dynamics simulations
复制标题
通过分子动力学模拟研究石墨烯气凝胶的机械性能和结构完整性
DOI：
10.1039/d3cp02585c
复制
发表时间：
2023
影响因子：
3.3
通讯作者：
Gu, Grace X.
中科院分区：
文献类型：
--
作者：
Zheng, Bowen;Liu, Chen;Li, Zhou;Carraro, Carlo;Maboudian, Roya;Senesky, Debbie G.;Gu, Grace X.
石墨烯气凝胶 (GA) 是一种基于 2D 石墨烯片的 3D 碳基纳米结构，因其是有史以来合成的最轻的固体材料而闻名。由于其超高孔隙率，它还具有许多其他优异的性能，例如高比表面积和大液体吸收能力。在计算方面，GA 的机械性能已通过分子动力学 (MD) 模拟进行了研究，揭示了实验观察之外的纳米级机制。然而，关于遗传算法结构和性质如何响应模拟参数变化而演变的研究一直缺乏，这为实验人员提供了宝贵的见解。此外，通过模拟和实验测量计算出的特性之间的差异很少被讨论。为了解决上述缺点，在本研究中，我们系统地研究了遗传算法的各种机械性能和结构完整性作为各种模拟参数的函数。结果表明，在计算机模拟 GA 制备过程中，较小且较少的球形夹杂物（模拟实验中水簇的影响）有利于强度和刚度，但可能导致脆性。此外，MD 模拟中结构有效的 GA 要求每个原子的键数至少为 1.40，否则 GA 构建块不会完全互连。最后，我们的计算结果与实验进行比较，以展示模拟技术的能力和局限性。这项工作可能有助于改进遗传算法以及其他新型纳米材料的计算方法。
Graphene aerogel (GA), a 3D carbon-based nanostructure built on 2D graphene sheets, is well known for being the lightest solid material ever synthesized. It also possesses many other exceptional properties, such as high specific surface area and large liquid absorption capacity, thanks to its ultra-high porosity. Computationally, the mechanical properties of GA have been studied by molecular dynamics (MD) simulations, which uncover nanoscale mechanisms beyond experimental observations. However, studies on how GA structures and properties evolve in response to simulation parameter changes, which provide valuable insights to experimentalists, have been lacking. In addition, the differences between the calculated properties via simulations and experimental measurements have rarely been discussed. To address the shortcomings mentioned above, in this study, we systematically study various mechanical properties and the structural integrity of GA as a function of a wide range of simulation parameters. Results show that during the in silico GA preparation, smaller and less spherical inclusions (mimicking the effect of water clusters in experiments) are conducive to strength and stiffness but may lead to brittleness. Additionally, it is revealed that a structurally valid GA in the MD simulation requires the number of bonds per atom to be at least 1.40, otherwise the GA building blocks are not fully interconnected. Finally, our calculation results are compared with experiments to showcase both the power and the limitations of the simulation technique. This work may shed light on the improvement of computational approaches for GA as well as other novel nanomaterials.