Formation of ordered ice nanotubes inside carbon nanotubes

We report simulations of the behaviour of water encapsulated in carbon nanotubes that suggest the existence of a variety of new ice phases not seen in bulk ice, and of a solid– liquid critical point

Kenichiro Koga; G. T. Gao; Hideki Tanaka; X. C. Zeng

2002

Scholarcy highlights

  • A comparison of the snapshot of the hexagonal ice nanotube with that of the liquid in the single-walled carbon nanotubes shows that the solid phase has a hollow-tube structure whereas the liquid phase has not
  • Summary: Following their discovery1, carbon nanotubes have attracted interest for their unusual electrical and mechanical properties, and because their hollow interior can serve as a nanometre-sized capillary2, 3, 4, 5, 6, 7, mould8, 9, 10, 11 or template12, 13, 14 in material fabrication
  • Intriguing is the conjecture16 that matter within the narrow confines of a carbon nanotube might exhibit a solid–liquid critical point17 beyond which the distinction between solid and liquid phases disappears
  • This unusual feature, which cannot occur in bulk material, would allow for the direct and continuous transformation of liquid matter into a solid
  • We report simulations of the behaviour of water encapsulated in carbon nanotubes that suggest the existence of a variety of new ice phases not seen in bulk ice, and of a solid– liquid critical point
  • Using carbon nanotubes with diameters ranging from 1.1 nm to 1.4 nm and applied axial pressures of 50 MPa to 500 MPa, we find that water can exhibit a first-order freezing transition to hexagonal and heptagonal ice nanotubes, and a continuous phase transformation into solid-like square or pentagonal ice nanotubes
  • Grand-potential density Phase equilibria of water confined in an open-ended carbon nanotube in contact with bulk water at fixed chemical potential μ and temperature T are determined from the minima of grand-potential density, ω =/V, where F and V are the Helmholtz free energy and the volume of the interior

Need more features? Save interactive summary cards to your Scholarcy Library.