Molecular Dynamics Simulation Of The Behavior Of Water In Carbon Nanotube

Water is one of the substances closely related to the phenomenon of life, in terms of the organisms, water transport is significant for the physiological activities of organisms. An essential protein which is in relation to these activities is water channel protein, which is also called aquaporin. It can adjust the intracellular osmotic pressure. Water molecules in this channel present one-dimensional water chain, if radius of carbon nanotube is obtained suitably, we can find this one-dimensional water chain structure, and in addition because of the simple and stable structure, carbon nanotube can be used as a simplified model when conducting research on water transport in aquaporin.The research on the behavior of water in carbon nanotube is of great significance for the transportation of water in biological systems. Water channels in living organisms are much more complex than that in carbon nanotube, and the charge is essential in the nanochannel, physiological solution and membrane protein, therefore by the introduction of charge to the carbon nanotube to simulate more realistic water channel in organisms is necessary. Although many scholars in this field have done a number of researches, so far, there is yet no work in experiment and simulation to study the behavior of water molecules in carbon nanotube by the effect of different charge magnitude. We applied charged carbon nanotubes as a model to study the impact of different magnitude of charge on the arrangement and transportation of water molecules in carbon nanotube by molecular dynamics simulation.Through our simulation we found that water molecules are very sensitive to changes in charge magnitude in the transportation of carbon nanotube, with the increasing of the charge, mobility of water molecules through the tube declined, when the magnitude of charge was greater than or equal to0.6e the flow across carbon nanotube can be negligible, carbon nanotubes have been completely closed, which is closely related to the phenomenon of structure of the water molecules in the tube. As water molecules in carbon nanotube form a fully stable dipole orientation, the flow of water molecules through the carbon nanotube is completely truncated.