Manikas A C, Pastore Carbone M G, Woods C R, Wang Y, Souli I, Anagnostopoulos G, Hadjinicolaou M, Novoselov K S, Galiotis C
Institute of Chemical Engineering, Foundation for Research and Technology Hellas (ICEHT/FORTH), Stadium St., Platani, 26504, Patras, Greece.
School of Physics and Astronomy, University of Manchester, Manchester, UK.
Nanoscale. 2019 Aug 1;11(30):14354-14361. doi: 10.1039/c9nr03166a.
The knowledge of the mechanism of stress transfer from a polymer matrix to a 2-dimensional nano-inclusion such as a graphene flake is of paramount importance for the design and the production of effective nanocomposites. For efficient reinforcement the shape of the inclusion must be accurately controlled since the axial stress transfer from matrix to the inclusion is affected by the axial-shear coupling observed upon loading of a flake of irregular geometry. Herein, we study true axial phenomena on regular- exfoliated-graphene micro-ribbons which are perfectly aligned to the loading direction. We exploit the strain sensitivity of vibrational wave numbers in order to map point-by-point the strain built up along the length of graphene. By considering the balance of shear-to-axial forces, we identify the shear stress at the interface and develop a universal inverse-length parameter that governs the stress transfer process at the nanoscale. An important parameter that has come out of this approach is the prediction and measurement of the transfer length that is required for efficient stress in these systems.
了解应力从聚合物基体传递到二维纳米夹杂物（如石墨烯薄片）的机制对于有效纳米复合材料的设计和生产至关重要。为了实现高效增强，夹杂物的形状必须精确控制，因为从不规则几何形状薄片加载时观察到的轴向 - 剪切耦合会影响从基体到夹杂物的轴向应力传递。在此，我们研究与加载方向完美对齐的规则剥离石墨烯微带中的真实轴向现象。我们利用振动波数的应变敏感性，逐点绘制沿石墨烯长度积累的应变。通过考虑剪切力与轴向力的平衡，我们确定界面处的剪应力，并开发一个通用的逆长度参数来控制纳米尺度的应力传递过程。这种方法得出的一个重要参数是预测和测量这些系统中实现有效应力所需的传递长度。
