Water Transport through Carbon Nanotubes with the Radial Breathing Mode

TL;DR

This study uses molecular dynamics simulations to show that the radial breathing mode of carbon nanotubes significantly enhances water transport by disrupting hydrogen bonds, especially at specific resonant frequencies, informing nanochannel design.

Contribution

It reveals the resonant effect of the radial breathing mode on water permeation in carbon nanotubes, a novel insight into nanoscale water transport mechanisms.

Findings

RBM increases water flux dramatically at 5000-11000 GHz

Hydrogen bonds in water chains are broken by RBM

Transport properties are unaffected outside the resonant frequency range

Abstract

Molecular dynamics simulations are performed to investigate the water permeation across the single-walled carbon nanotube (SWCNT) with the radial breathing mode (RBM) vibration. It is found that the RBM can play a significant role in breaking hydrogen bonds of the water chain, accordingly increasing the net flux dramatically, and reducing drastically the average number of water molecules inside the tube with the frequency ranging from 5000 to 11000 GHz, while far away from this frequency region the transport properties of water molecules are almost unaffected by the RBM. This phenomenon can be understood as the resonant response of the water molecule chain to the RBM. Our findings are expected to be helpful for the design of high-flux nanochannels and the understanding of biological activities especially the water channelling.