CAPILLARY PENETRATION OF LIQUID DROPLETS INTO POROUS MATERIALS

The behavior of a liquid droplet placed on a porous solid is considered. A model is developed for the infiltration of finitesize liquid droplets into porous materials, including the effects of the instantaneous droplet size on the number of pores in contact with the droplet. Simple analytical solutions are developed for the time dependence of the droplet radius under two limiting case assumptions concerning the kinetic behavior of the droplet as its volume is depleted. The two limiting cases are seen to represent upper and lower limits on the liquid depletion time. Liquid depletion data of silicone liquids on a soda-lime-silicate porous solid are presented and compared with predictions of the models. © 1993 Academic Press. All rights reserved.