Elastic modulus scaling in graphene-metal composite nanoribbons
Elastic modulus scaling in graphene-metal composite nanoribbons
复制标题
DOI：
10.1088/1361-6463/ab7329
复制
发表时间：
2020-03
期刊：
影响因子：
--
通讯作者：
Kaihao Zhang;Mitisha Surana;R. Haasch;S. Tawfick
中科院分区：
文献类型：
--
作者：
Kaihao Zhang;Mitisha Surana;R. Haasch;S. Tawfick
本研究探讨了石墨烯包裹钯纳米带的石墨烯-金属复合材料的合成和力学行为。利用化学气相沉积（CVD）技术在钯纳米带表面涂覆石墨烯，可以显著提高钯纳米带的弹性模量。这些测量是通过悬浮微桥压痕进行的。一种改进的压痕测量方法仔细考虑了由非理想桥梁几何形状引起的不确定性。测量到的复合模量取决于带的厚度在36 - 250 nm之间，36 nm厚的纳米带测量到的最大模量为147 GPa，比未涂覆的Pd纳米带增加了41.6%。结果清楚地表明，石墨烯由于其高模量和与Pd的强相互作用，可以有效地增强厚度达250 nm的Pd纳米带，相当于0.54%的体积分数。我们通过推导考虑二维石墨烯“表面”增强的三维“大块”金属纳米带的混合模型的数学规则来研究模量标度。这种建模方法的灵感来自于表面模量的框架，表面模量通常用于解释在亚10nm范围内观察到的纳米线和纳米带模量的偏差。在这里，纳米带要厚得多，但石墨烯的极高模量导致测量到的复合模量增加。此外，在这些计算中，我们考虑了石墨烯的非线性模量分量的关键作用-它对应变的二次依赖-这是由石墨烯和Pd之间的晶格错配引起的界面应变引起的。石墨烯-钯复合纳米带和薄膜在从应变工程催化到耐损伤柔性电子器件的广泛应用中非常有用。除了纳米带之外，所提出的3D/2D混合规则模型可用于解释3D/2D异质结构和通过粉末混合路线制备的块体石墨烯-金属纳米复合材料的模量缩放。
This study addresses the synthesis and mechanical behavior of graphene-metal composites comprising palladium (Pd) nanoribbons wrapped with graphene. Coating Pd nanoribbons with graphene by chemical vapor deposition (CVD) considerably increases their elastic modulus. These measurements are made by suspended microbridge indentation. A refined indentation measurement approach carefully takes into consideration the uncertainty resulting from the non-ideal bridge geometry. The measured composite moduli depend on the ribbon thickness in the range of 36–250 nm, with the maximum modulus of 147 GPa measured for 36 nm thick nanoribbons, representing an increase of 41.6% over uncoated Pd nanoribbons. The results clearly demonstrate that graphene, owing to its high modulus and strong interaction with Pd, can effectively reinforce Pd nanoribbons up to thickness of 250 nm, which corresponds to a volume fraction of 0.54%. We study the modulus scaling by deriving a mathematical rule of mixture model considering 3D ‘bulk’ metal nanoribbons reinforced by the 2D graphene ‘surface’. This modeling approach is inspired by the framework of surface modulus, which is typically employed to explain the deviations in the moduli of nanowires and nanoribbons observed in the sub-10 nm regime. Here, the nanoribbons are much thicker, yet graphene’s extremely high modulus leads to the observed increase in the measured composite moduli. Further, in these calculations, we consider the critical role of the nonlinear modulus component of graphene -its quadratic dependence on strain- which results from the lattice mismatch-induced interfacial strains between graphene and Pd. Graphene-Pd composite nanoribbons and thin films can be very useful for a wide range of application ranging from strain-engineered catalysis to damage tolerant flexible electronic devices. Beyond nanoribbons, the proposed 3D/2D rule of mixture model may be used to explain the modulus scaling in 3D/2D heterostructures and in bulk graphene-metal nanocomposites made by powder mixing routes.