Pullout simulations were conducted to investigate the interfacial shear properties between defective graphene (DGr) and polymethyl methacrylate (PMMA) through molecular dynamics simulations with ReaxFF reactive force fields. The effects of number of defects (Stone‐Wales [SW] and double‐vacancy [DV] defects) were investigated. Our results showed that these two types of defects can obviously enhance the interfacial shear strengths of DGr /PMMA nanocomposites. And the DV defects have a greater contribution to the interfacial shear strength enhancement compared to the SW defects. Analysis of the morphology of DGr indicated that surface roughness, which was induced by defects, plays an important role in enhancing the interfacial shear strength at the interface between the DGr and PMMA. Moreover, the effects of chemical functionalization at the defect sites were also investigated. We observed that the CO bonds of functional groups (hydroxyls) at defect sites inclined from the datum plane (z = 0 plane) of the graphene sheet. The inclination of CO bonds, which weakened the mechanical interlocking between functional graphene and PMMA matrix, differently influenced by the DV defect and SW defect.

中文翻译：

---

缺陷对石墨烯与聚甲基丙烯酸甲酯界面剪切特性的影响

通过具有ReaxFF反作用力场的分子动力学模拟，进行拉拔模拟以研究缺陷石墨烯（DGr）和聚甲基丙烯酸甲酯（PMMA）之间的界面剪切性能。研究了缺陷数量（Stone-Wales [SW]和双空位[DV]缺陷）的影响。我们的结果表明，这两种类型的缺陷可以明显提高DGr / PMMA纳米复合材料的界面剪切强度。与SW缺陷相比，DV缺陷对界面剪切强度的提高具有更大的贡献。DGr的形态分析表明，由缺陷引起的表面粗糙度在提高DGr与PMMA之间的界面剪切强度方面起着重要作用。此外，还研究了缺陷部位化学功能化的影响。我们观察到C在从石墨烯片的基准平面（z = 0平面）倾斜的缺陷位点的官能团（羟基）的O-键。CO键的倾斜减弱了功能性石墨烯与PMMA基体之间的机械互锁，受DV缺陷和SW缺陷的影响不同。