The Effect Of Electric Field Direction On The Transport Properties Of Water Molecules In Nanopores

Transportation of water across nanochannels is of great importance for biolocical activities as well as for designing novel molecular device,machines or sensors.With the development of experimental and computational facilities,it becomes possible to study the water dynamics inside and across the nanoscale channels by both experiments and simulations.When the radius of a nanochannel is small enough,the water molecules inside the channel form a single-file structure.Water confined in these nanoscale channels usually exhibits different dynamics not seen in the bulk system.It has been proved that water can be transported across the nanochannel as a single-file structure in(6,6)cabon nanochannel.But it's still a difficult subject that how to control the flux of water.Transport properties of water through a nanochannel influenced by the direction of external electric field has been investigated by using molecular dynamics simulations.We found a critical angle ?_c between the external field and the nanochannel axis.The average net water flux increases as ? increases for ???_c but decreases sharply to a near-zero value for a further increase of ?.The maximum value of the average net water flux is 7.33 times as high as the value when the electric field is along the nanochannel axis.In order to finger out the mechanism inside,on the one hand,we calculated the direction of the water diple in nanochannel with diferent angle of electric field,statistic the probability profile of the direction of water diple and the relateionship with flux of water,showing that The dipole moment of water molecule plays a decisive role in the transport direction of water molecules,on the other hand,compared The interaction potential of water molecules and the change of the number of water molecules and hydrogen bonds in the channel with different electric field directions,showing that the asymmetric interaction potential between water molecules in the channel is the driving factor for the transport of water molecules.Therefore,the direction of the electric field actually change the net flow of water transportation through the hole,by influence the polarization direction of the water molecules and the interaction potential between water molecules in the channel.Our findings are of great practical importance for nanomolecular cnginccring,which provide a possiblc strategy for designing novel controllable water nanopumps.