Lamellar water induced quantized interlayer spacing of nanochannels walls

The nanoscale confinement is of great important for the industrial applications of molecular sieve, desalination, and also essential in biological transport systems. Massive efforts have been devoted to the influence of restricted spaces on the properties of confined fluids. However, the situation of channel-wall is crucial but attracts less attention and remains unknown. To fundamentally understand the mechanism of channel-walls in nanoconfinement, we investigated the interaction between the counter-force of the liquid and interlamellar spacing of nanochannel walls by considering the effect of both spatial confinement and surface wettability. The results reveal that the nanochannel stables at only a few discrete spacing states when its confinement is within 1.4 nm. The quantized interlayer spacing is attributed to water molecules becoming laminated structures, and the stable states are corresponding to the monolayer, bilayer and trilayer water configurations, respectively. The results can potentially help to understand the characterized interlayers spacing of graphene oxide membrane in water. Our findings are hold great promise in design of ion filtration membrane and artificial water/ion channels.