Delamination Mechanics of Carbon Nanotube Micropillars
Delamination Mechanics of Carbon Nanotube Micropillars
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DOI：
10.1021/acsami.9b09979
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发表时间：
2019-09-25
影响因子：
9.5
通讯作者：
Maschmann, Matthew R.
中科院分区：
文献类型：
--
作者：
Brown, Josef;Hajilounezhad, Taher;Maschmann, Matthew R.
碳纳米管（CNT）森林与其生长基底的粘附性是许多应用的关键问题。在这里，我们测量了脱层力的CNT森林微柱使用原位扫描电子显微镜（SEM）拉伸测试。具有环氧树脂粘合剂的平坦尖端首先与独立式CNT柱的顶表面建立接触，然后以位移控制的张力拉动柱，直到观察到分层。基于全柱横截面积，测量到6.1MPa的平均分层应力，并且观察到在催化剂颗粒和生长基底之间发生分离。碳纳米管森林分层的有限元模拟表明，力和应变是不均匀分布在碳纳米管之间的拉伸加载过程中，碳纳米管逐渐失去附着力的位移增加。基于结合的实验和模拟，约350 MPa的粘附强度估计每个CNT和基板之间。这些研究结果提供了重要的洞察CNT应用，如热界面，机械传感器，和结构复合材料，同时也表明了一个潜在的上限，在CNT森林合成过程中允许的张力。
The adhesion of carbon nanotube (CNT) forests to their growth substrate is a critical concern for many applications. Here, we measured the delamination force of CNT forest micropillars using in situ scanning electron microscopy (SEM) tensile testing. A flat tip with epoxy adhesive first established contact with the top surface of freestanding CNT pillars and then pulled the pillars in displacement-controlled tension until delamination was observed. An average delamination stress of 6.1 MPa was measured, based on the full pillar cross-sectional area, and detachment was observed to occur between catalyst particles and the growth substrate. Finite element simulations of CNT forest delamination show that force and strain are heterogeneously distributed among CNTs during tensile loading and that CNTs progressively lose adhesion with increased displacement. Based on combined experiments and simulations, an adhesion strength of approximately 350 MPa was estimated between each CNT and the substrate. These findings provide important insight into CNT applications such as thermal interfaces, mechanical sensors, and structural composites while also suggesting a potential upper limit of tensile forces allowed during CNT forest synthesis.