Physik Department, Technische Universität München, Garching 85748, Germany.
J Phys Condens Matter. 2011 May 11;23(18):184110. doi: 10.1088/0953-8984/23/18/184110. Epub 2011 Apr 20.
We study water flow through carbon nanotubes using continuum theory and molecular dynamics simulations. The large slip length in carbon nanotubes greatly enhances the pumping and electrokinetic energy conversion efficiency. In the absence of mobile charges, however, the electro-osmotic flow vanishes. Uncharged nanotubes filled with pure water can therefore not be used as electric field-driven pumps, contrary to some recently ventured ideas. This is in agreement with results from a generalized hydrodynamic theory that includes the angular momentum of rotating dipolar molecules. The electro-osmotic flow observed in simulations of such carbon nanotubes is caused by an imprudent implementation of the Lennard-Jones cutoff. We also discuss the influence of other simulation parameters on the spurious electro-osmotic flow.
我们使用连续介质理论和分子动力学模拟研究了水在碳纳米管中的流动。碳纳米管中的大滑移长度极大地提高了泵送和电动能转换效率。然而，在没有可移动电荷的情况下，电渗流会消失。因此，不带电荷的充满纯水的纳米管不能像电场驱动的泵一样使用，这与最近提出的一些观点相反。这与包括旋转偶极分子角动量的广义流体动力学理论的结果一致。在对这种碳纳米管的模拟中观察到的电渗流是由于对 Lennard-Jones 截止的不当实现引起的。我们还讨论了其他模拟参数对虚假电渗流的影响。
