Kinetics of liquid penetration into periodically constricted capillaries

Abstract

An equation is derived for the rate of penetration of a liquid into a periodically constricted tube (PCT) of capillary dimensions. Its solution yields an apparent diameter for the PCT. A comparison of predicted and experimentally derived values of D_app for sinusoidal tubes shows good agreement. Examination of the rate equation indicates that under certain conditions, the meniscus is arrested. This is verified by free-energy calculations. The implications of this phenomenon for the modelling of liquid penetration into porous structures are discussed briefly.