title: Capillary rise of water in hydrophilic nanopores.
abstract: We report on the capillary rise of water in three-dimensional networks of hydrophilic silica pores with 3.5 nm and 5 nm mean radii, respectively (porous Vycor monoliths). We find classical square root of time Lucas-Washburn laws for the imbibition dynamics over the entire capillary rise times of up to 16 h investigated. Provided we assume two preadsorbed strongly bound layers of water molecules resting at the silica walls, which corresponds to a negative velocity slip length of -0.5 nm for water flow in silica nanopores, we can describe the filling process by a retained fluidity and capillarity of water in the pore center. This anticipated partitioning in two dynamic components reflects the structural-thermodynamic partitioning in strongly silica bound water layers and capillary condensed water in the pore center which is documented by sorption isotherm measurements.
authors: Faculty of Physics and Mechatronics Engineering, Saarland University, D-66041 Saarbrücken, Germany. s.gruener@mx.uni-saarland.de
authors: Simon
authors: S
authors: Gruener
authors: Tommy
authors: T
authors: Hofmann
authors: Dirk
authors: D
authors: Wallacher
authors: Andriy V
authors: AV
authors: Kityk
authors: Patrick
authors: P
authors: Huber