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 Dapp 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.