Hot channels engineer enhanced water transport

Abstract

Designing the high-flux nanofluidic devices is still a challenge. In this work, we show by molecular dynamics simulations that the permeation of single-file water molecules through a carbon nanotube (CNT) can be significantly enhanced by means of heating up the CNT. Specifically, with the increase in channel temperature, the water flow exhibits a remarkable maximum behavior, corresponding to the decrease in water occupancy. The maximum flow is clearly caused by the channel vibration at high temperatures that leads to the breakdown of single-file water chain, suggesting a new mechanism for fast water conduction. Furthermore, with the increase in channel temperature, the water translocation time decreases monotonously and the flipping frequency of water dipole orientation increases as a whole. The distributions of occupancy, hydrogen bond number, dipole angle and axial density profiles also demonstrate unique behaviors and suggest the breakdown of single-file water chain. Our results provide a significant new method to breakdown the collective motion of single-file water chain and achieve the fast water transport, which is helpful for the design of high-flux nanofluidic devices.