Molecular Modeling of Mercury Porosimetry

Abstract We present a molecular thermodynamic approach to model mercury porosimetry. A lattice model is used to describe the intrusion/extrusion of mercury into different pore structures. The non-wetting nature of mercury is modeled by setting the wall-fluid interaction of the lattice model to repulsive values. We perform Mean-Field Density Functional Theory calculations on a mesoporous Vycor glass for different temperatures. The shape of the intrusion/extrusion curves is in good agreement with experimental observations. Visualizations of the liquid distribution in the Vycor glass reveal a fragmentation of mercury along the extrusion curve. The calculations performed on ink-bottle pore show that this fragmentation is caused by the snap-off of mercury from the necks leading to a droplet of mercury entrapped into the bottle part of the pore. This phenomenon is likely to play a role in the mechanism of mercury entrapment frequently observed during experiments.