Compression Behavior of Single-Layer Graphenes
Compression Behavior of Single-Layer Graphenes
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DOI：
10.1021/nn100454w
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发表时间：
2010-06-01
期刊：
影响因子：
17.1
通讯作者：
Galiotis, Costas
中科院分区：
文献类型：
--
作者：
Frank, Otakar;Tsoukleri, Georgia;Galiotis, Costas
涉及单层石墨烯的大多数应用的核心是它在各种应力状态下的机械响应。迄今为止报道的大部分工作都是理论性的，涉及模型石墨烯的拉伸和压缩载荷。大多数实验工作确实局限于单个薄片在空气中的弯曲和薄片的拉伸，通常类似于使用塑料基材的1%。最近，我们已经证明，通过采用悬臂梁，我们可以使单个石墨烯受到不同程度的轴向压缩。在这里，我们通过详细测量不同几何形状的单个薄片的应力吸收和压缩屈曲应变，进一步扩展了这项工作。在所有情况下，通过石墨烯的G或2D声子的位移，同时进行拉曼测量来监测机械响应。尽管单层石墨烯的厚度无限小，但结果表明，嵌入塑性梁的石墨烯表现出显著的压缩屈曲应变。当长宽比（>= 0.2）较大时，屈曲应变为-0.5% ~ -0.6%。然而，当I/w < 0.2时，即使高于-1%，也没有观察到应变的破坏。基于经典欧拉分析的计算表明，与悬浮在空气中的石墨烯相比，聚合物横向支撑提供的屈曲应变增强超过6个数量级。
Central to most applications involving monolayer graphenes is its mechanical response under various stress states. To date most of the work reported is of theoretical nature and refers to tension and compression loading of model graphenes. Most of the experimental work is indeed limited to the bending of single flakes in air and the stretching of flakes up to typically similar to 1% using plastic substrates. Recently we have shown that by employing a cantilever beam we can subject single graphenes to various degrees of axial compression. Here we extend this work much further by measuring in detail both stress uptake and compression buckling strain in single flakes of different geometries. In all cases the mechanical response is monitored by simultaneous Raman measurements through the shift of either the G or 2D phonons of graphene. Despite the infinitely small thickness of the monolayers, the results show that graphenes embedded in plastic beams exhibit remarkable compression buckling strains. For large length (I)-to-width (w) ratios (>= 0.2) the buckling strain is of the order of -0.5% to -0.6%. However, for I/w < 0.2 no failure is observed for strains even higher than -1%. Calculations based on classical Euler analysis show that the buckling strain enhancement provided by the polymer lateral support is more than 6 orders of magnitude compared to that of suspended graphene in air.