Agglomeration Dynamics of 1D Materials: Gas-Phase Collision Rates of Nanotubes and Nanorods
Agglomeration Dynamics of 1D Materials: Gas-Phase Collision Rates of Nanotubes and Nanorods
复制标题
DOI：
10.1002/smll.201900520
复制
发表时间：
2019-07-01
期刊：
影响因子：
13.3
通讯作者：
Smail, Fiona
中科院分区：
文献类型：
--
作者：
Boies, Adam M.;Hoecker, Christian;Smail, Fiona
气相一维材料在人为和自然系统中的聚集和自组装决定了它们的纳米级形貌、多尺度层次结构和最终的宏观尺度性质。布朗运动引起碰撞，在这种碰撞中，一维材料经常重组形成束，并可能导致气凝胶。本文给出了一维纳米材料在热输运过程中碰撞率的初步结果。纳米管旋转和平移的Langevin动力学模拟表明，刚性纳米管或纳米棒的碰撞核大约是球形系统的10倍。由此产生的降阶方程允许直接计算物理参数，以确定长度为10(2)至10(6)nm的直线和弯曲一维材料的碰撞核。相对于刚性材料，弯曲一维结构的长碰撞核增加约1.3倍（约10(2)nm），短碰撞核增加约5倍（约10(2)nm）。碰撞频率的应用允许首次对气相碳纳米管（CNTs）的气凝胶自组装进行动力学分析。碳纳米管碰撞和束形成的时间尺度（0.3-42秒）与碳纳米管反应器中的经验停留时间（3-15秒）一致。这些结果为气凝胶形成所需的碳纳米管长度、数量和时间尺度提供了见解，从而增强了我们对大规模生产的1D气凝胶材料的理解。
The agglomeration and self-assembly of gas-phase 1D materials in anthropogenic and natural systems dictate their resulting nanoscale morphology, multiscale hierarchy, and ultimate macroscale properties. Brownian motion induces collisions, upon which 1D materials often restructure to form bundles and can lead to aerogels. Herein, the first results of collision rates for 1D nanomaterials undergoing thermal transport are presented. The Langevin dynamic simulations of nanotube rotation and translation demonstrate that the collision kernels for rigid nanotubes or nanorods are approximate to 10 times greater than spherical systems. Resulting reduced order equations allow straightforward calculation of the physical parameters to determine the collision kernel for straight and curved 1D materials from 10(2) to 10(6) nm length. The collision kernels of curved 1D structures increase approximate to 1.3 times for long (>10(2) nm), and approximate to 5 times for short (approximate to 10(2) nm) relative to rigid materials. Applications of collision frequencies allow the first kinetic analysis of aerogel self-assembly from gas-phase carbon nanotubes (CNTs). The timescales for CNT collision and bundle formation (0.3-42 s) agree with empirical residence times in CNT reactors (3-15 s). These results provide insights into the CNT length, number, and timescales required for aerogel formation, which bolsters our understanding of mass-produced 1D aerogel materials.