Evaluating the forces generated during carbon nanotube forest growth and self-assembly
Evaluating the forces generated during carbon nanotube forest growth and self-assembly
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DOI：
10.1016/j.mtla.2019.100371
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发表时间：
2019-09-01
期刊：
影响因子：
3.4
通讯作者：
Maschmann, Matthew R.
中科院分区：
文献类型：
--
作者：
Hajilounezhad, Taher;Ajiboye, Damola M.;Maschmann, Matthew R.
使用力学有限元模型研究了活跃生长和相互作用的碳纳米管（CNT）森林产生的时间分辨反作用力。CNT-CNT相互作用力被传递到位于每个CNT底部的CNT催化剂颗粒，这可以改变催化剂动力学并调节CNT生长速率。模拟结果表明，碳纳米管的增长速度大于人口平均传输压缩力的催化剂颗粒，而那些增长速度较慢的传输张力。以群体平均值的+/-10%的速率生长的CNT的力的大小在100纳米牛顿的量级上，对应于GPa量级的应力。当使用一个类Arrhenius的动力学模型来调节CNT的生长速率，较慢的CNT的生长速率提高了张力，而生长较快的CNT的生长速率降低了压缩力。力调制动力学的净结果是反作用力减小大约一个数量级。了解一个单独的CNT的生长参数是如何与CNT森林组装过程中所经历的机械力和整体CNT形态有关，预计将改善CNT森林形态和整体森林特性的控制。
The time-resolved reaction forces generated by actively growing and interacting carbon nanotube (CNT) forests are investigated using a mechanical finite element model. The CNT-CNT interaction forces are transmitted to the CNT catalyst particle residing at the base of each CNT, which may alter catalyst kinetics and modulate CNT growth rate. The simulation shows that CNTs growing at a rate greater than the population average transmit compressive force to the catalyst particle, while those growing at a slower rate transmitted tensile force. The magnitude of force for CNTs growing at a rate that was +/- 10% of the population average was on the order of 100's of nanonewtons, corresponding to stress on the order of GPa. When using an Arrhenius-like kinetic model to modulate CNT growth rates, the growth rate of slower CNTs was enhanced by tensile forces, while the growth rate of faster growing CNTs was decreased by compressive forces. The net result of the force-modulation kinetics was a reaction force reduction of approximately an order of magnitude. Understanding how the growth parameters of an individual CNT are related to the mechanical forces it experiences during CNT forest assembly and the overall CNT morphology is expected to improve the control of CNT forest morphology and ensemble forest properties.