Modeling the abnormally slow infiltration rate in mesoporous films

CLAUDIO L. A. BERLI; MAGALÍ MERCURI; MARTIN G. BELLINO

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2017 vol. 19 p. 1731 - 1734

1463-9076

Mesoporous films exhibit striking behaviors in capillary-driven infiltration experiments. The process follows the classical Lucas-Washburn dynamics, but the effective pore radius associated to the hydrodynamic resistance results orders of magnitude lower than measured pore dimensions. In addition, the infiltration rate decreases with pore diameter, in contradiction with the expected trend for capillary-like pores. A simple model that account for the mechanism behind these anomalous effects is presented here. It is found that the infiltration rate is inversely proportional to the cubed ratio of pore to neck size. This physical scaling correctly represents both the magnitude of the infiltration rate and its variation with pore diameters, for a wide range of experimental data. The model establishes a connection between capillary filling dynamics and nanoscale pore structure, which is of practical interest for the design and characterization of mesoporous films.