Effects of Orthogonal Electric Field on Water Flux through a Carbon Nanotube

Water transport in nanopores is important for many biological processes and the design of nanodevices. It has been demonstrated that water molecules are transported through a (6,6)-type carbon nanotube (CNT) by forming single-file chains. However, a controllable water flow through a CNT remains difficult to achieve. In this paper, we investigated how to control the net flux of water molecules transported through a CNT and the on-off gating behavior of the CNT using an orthogonal electric field. With a 200 MPa pressure difference acting on the top of the first layer of water molecules as the driving force, the net flux of water molecules decreased linearly as the orthogonal electric field strength (E) increased from 1 to 3 V . nm(-1). When E increased over 3 V . nm(-1), the flow of water molecules through the CNT was turned off and the net flux was almost zero. Both the orientation of water dipoles and flipping frequency were strongly correlated with the water occupancy in this case.