Translational dynamics of water in the nanochannels of oriented chrysotile asbestos fibers

We performed a high-resolution quasielastic neutron scattering study of water dynamics in fully hydrated oriented chrysotile asbestos [chemical formula Mg3Si2O5(OH)4] fibers. The fibers possess sets of macroscopically long, parallel channels with a characteristic diameter of about 5nm. Freezing of water in the channels was observed at about 237K. Measurements at 280, 260, and 240K revealed a translational dynamics of water molecules with the relaxation time slower by more than an order of magnitude compared to bulk water. The Q dependence of the quasielastic broadening was typical of a translational diffusion motion with a distribution of jump lengths, similar to that observed in bulk water. The relaxation time showed no significant anisotropy in the measurements with the scattering vector parallel and perpendicular to the fiber axes.