Pure water has been drawn into open-ended single-walled carbon nanotubes (with diameters ranging from 1.1 to 1.4 nm). Once encapsulated, the behaviour of the confined water has been investigated from temperatures of 320 to 240 K and applied axial pressures of 50–500 MPa using molecular dynamics simulations.
The results have indicated a variety of new ice phases that are not seen in bulk ice and a solid–liquid critical point where the distinction between solid and liquid phases disappears is observed. The water has been observed to exhibit first-order freezing transitions to hexagonal and heptagonal ice nanotubes, and a continuous phase change into solid-like square or pentagonal ice nanotubes.
Formation of ordered ice nanotubes inside carbon nanotubes.
