Complex filling dynamics in mesoporous thin films

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

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington; Año: 2017 vol. 33 p. 152 - 157

0743-7463

The fluid front dynamics resulting from the coexisting infiltration and evaporation phenomena in nanofluidic systems has been investigated. More precisely, water infiltration in both titania and silica mesoporous films was studied through a simple experiment: a sessile drop was deposited over the film and the advancement of the fluid front into the porous structure was optically followed and recorded in time. In the case of titania mesoporous films, capillary infiltration arrested at a given distance, and a steady annular region of wetted material was formed. A simple model that combines Lucas-Washburn infiltration and surface evaporation was derived, which appropriately describes the observed filling dynamics and the annulus width in dissimilar mesoporous morphologies. In the case of worm-like mesoporous morphologies, a remarkable phenomenon was found: instead of reaching a steady infiltration-evaporation balance, the fluid front exhibits an oscillating behavior. This complex filling dynamics opens interesting possibilities to study unusual nanofluidic phenomena, as well as to discover novel applications.