(37c) The Effects of Confinement on Water Structure and Dynamics: a Molecular Simulation Study

Water confined in carbon nanostructures interestingly shows an ordered, ice-like structure. These structures can be potentially used as proton-conductor media. Such ice-like structure may have however different structural and dynamical properties than those of ice. We performed classical molecular dynamics simulations to characterize the structure and dynamics of water at room temperature and a density of 1 g/cm³ within graphite walls of different separations, and establish differences between structural and dynamical properties of confined water and those of low-temperature water at the same density that could be useful to describe the environment in which a proton would move under these conditions. The results show the formation of well-ordered and parallel to the graphite surfaces of water layers. For larger separations additional water layers are formed in the pore center, and the diffusion coefficient increases. The mobilities of encapsulated water become similar to the one of low-temperature water (213 K) at a separation of 8 Å although they show very different structures.