Atomistic mechanisms of adhesion and shear strength in graphene oxide-polymer interfaces
Atomistic mechanisms of adhesion and shear strength in graphene oxide-polymer interfaces
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DOI：
10.1016/j.jmps.2021.104578
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发表时间：
2021-08-16
影响因子：
5.3
通讯作者：
Espinosa, Horacio D.
中科院分区：
文献类型：
--
作者：
Choi, Jin Y.;Zhang, Xu;Espinosa, Horacio D.
结合纳米复合材料界面的实验和计算研究是非常需要深入了解他们的性能。然而，有很少的文献报道，结合良好控制的原子力显微镜实验与分子动力学模拟，探讨高分子化学和组装对界面粘附和剪切强度的作用。在这项工作中，我们研究了基于珍珠状结构的纳米复合材料中普遍存在的氧化石墨烯（GO）-聚合物界面。通过比较GO-聚乙二醇（PEG）和GO-聚乙烯醇（PVA）的面外分离和面内剪切变形，研究了由货车德瓦耳斯和氢键相互作用引起的界面强度。研究揭示了无水GO-PVA系统在面外和面内变形模式下的整体更好的机械性能，突出了GO-PVA中存在的供体-受体氢键形成的益处。这种键形成导致链间氢键网络，从而导致更强的界面。相比之下，仅作为氢键受体的PEG主要依赖于货车范德华链间相互作用，通常导致较弱的相互作用。研究还预测，水的加入增加了GO-PEG的粘附力，但降低了GO-PVA的粘附力，并略微增加了两个系统的剪切强度。此外，通过比较模拟和实验，我们表明，CHARMM力场有足够的准确性，以捕捉聚合物含量，水分布的影响，并提供定量指导，实现最佳的界面性能。因此，该研究展示了一种有效的方法，在材料基因组的精神，对2D材料的设计，聚合物纳米复合材料系统的应用要求机械鲁棒性。
Combining experimental and computational studies of nanocomposite interfaces is highly needed to gain insight into their performance. However, there are very few literature reports, combining well-controlled atomic force microscopy experiments with molecular dynamic simulations, which explore the role of polymer chemistry and assembly on interface adhesion and shear strength. In this work, we investigate graphene oxide (GO)-polymer interfaces prevalent in nanocomposites based on a nacre-like architectures. We examine the interfacial strength resulting from van der Waals and hydrogen bonding interactions by comparing the out-of-plane separation and in-plane shear deformations of GO-polyethylene glycol (PEG) and GO-polyvinyl alcohol (PVA). The investigation reveals an overall better mechanical performance for the anhydrous GO-PVA system in both out-of-plane and in-plane deformation modes, highlighting the benefits of the donor-acceptor hydrogen bond formation present in GO-PVA. Such bond formation results in inter-chain hydrogen bond networks leading to stronger interfaces. By contrast, PEG, a hydrogen bond acceptor only, relies primarily on van der Waals inter-chain interactions, typically resulting in weaker interactions. The study also predicts that water addition increases the adhesion of GO-PEG but decreases the adhesion of GO-PVA, and slightly increases the shear strength in both systems. Furthermore, by comparing simulations and experiments, we show that the CHARMM force field has enough accuracy to capture the effect of polymer content, water distribution, and to provide quantitative guidance for achieving optimum interfacial properties. Therefore, the study demonstrates an effective methodology, in the Materials Genome spirit, toward the design of 2D materials-polymer nanocomposites system for applications demanding mechanical robustness.