Untangling the physics of water transport in boron nitride nanotubes.
Untangling the physics of water transport in boron nitride nanotubes.
复制标题
解开氮化硼纳米管中水传输的物理原理。
作者：
Mistry S
碳纳米管（CNTs）一直被认为是下一代膜的首选材料。一些研究表明，氮化硼纳米管（bnnt）可能比碳纳米管提供更高的纯水运输能力，而另一些研究则得出了相反的结论。在这项工作中，我们使用模拟和实验数据相结合的方法来揭示这种差异的原因，并详细研究了通过BNNT膜的流动阻力。通过将纳米管膜的阻力划分为贡献组分，我们研究了孔端结构、膜长度和BNNT原子部分电荷的影响。大多数BNNT膜的分子模拟研究使用连接到高压和低压储层的短膜。在这里我们发现这些短膜的流动阻力主要是由孔端阻力决定的，这使得通过纳米管和不同纳米管材料之间的比较来理解水的传输性能变得模糊。相比之下，纳米管内部的流动阻力支配着微尺度厚的实验室膜，而末端阻力往往可以忽略不计。因此，仅从纳米管的流动阻力来判断，我们发现CNTs的性能可能始终优于bnnt。此外，我们发现在我们的分子模拟中，BN原子上部分电荷的选择在流动阻力测量中起着很大的作用。本文重点介绍了分子模拟与实验结果比较的研究方向。
Carbon nanotubes (CNTs) have long been heralded as the material of choice for next-generation membranes. Some studies have suggested that boron nitride nanotubes (BNNTs) may offer higher transport of pure water than CNTs, while others conclude otherwise. In this work, we use a combination of simulations and experimental data to uncover the causes of this discrepancy and investigate the flow resistance through BNNT membranes in detail. By dividing the resistance of the nanotube membranes into their contributing components, we study the effects of pore end configuration, membrane length, and BNNT atom partial charges. Most molecular simulation studies of BNNT membranes use short membranes connected to high and low pressure reservoirs. Here we find that flow resistances in these short membranes are dominated by the resistance at the pore ends, which can obscure the understanding of water transport performance through the nanotubes and comparison between different nanotube materials. In contrast, it is the flow resistance inside the nanotubes that dominates microscale-thick laboratory membranes, and end resistances tend to be negligible. Judged by the nanotube flow resistance alone, we therefore find that CNTs are likely to consistently outperform BNNTs. Furthermore, we find a large role played by the choice of partial charges on the BN atoms in the flow resistance measurements in our molecular simulations. This paper highlights a way forward for comparing molecular simulations and experimental results.