Nanotube Water

Nanotube water, a one-dimensional form of water consisting of a string of water molecules confined in a carbon nanotube, has been studied with neutron scattering by physicists at Argonne National Lab. Neutron scattering measurements, along with computer simulations of the molecular interactions between the water and the surrounding single-walled carbon nanotube, confirmed that water molecules had successfully been taken up into the nanotubes in the form of a "wire." But this was not all; surrounding the water wire was another water structure, a sheath of water, a cylindrical square-ice- sheet formation (see figure).

The result of this novel architecture was that fluid-like behavior was observed at temperatures far below the freezing point of normal water. The hydrogen bonds along the water chain seem to be softened, allowing, for example, a freer movement of protons along the chain. The Argonne researchers (contact Alexander Kolesnikov, akolesnikov@anl.gov, 630-252-3555) believe that this anomalous behavior might help to explain other phenomena featuring nm-scale confined water such as water migration from soil to plants via xylem vessels and the proton translocation in transmembrane proteins. (Kolesnikov et al., Physical Review Letters, 16 July 2004.)