Changes in CNT-confined water structural properties induced by the variation in water molecule orientation

Using a (8, 8) carbon nanotube (CNT) as a model for nanochannel, we studied the effects of carbonyl (-CO) groups and external electric field on the properties of confined water molecules by molecular dynamics simulation. We analysed the density profiles, the distribution of orientation and the hydrogen bonds of water molecules in the axial and radial directions of the CNT. The results show that -CO groups are more powerful than electric fields on controlling water properties, and property changes induced by -CO groups are less affected by electric fields. Meanwhile, the particular behaviour of water molecules induced by the -CO groups is not limited near the -CO groups, but also expands to the whole CNT.