Multiple Meniscus Depinning Transitions in Open Capillary Slits

We investigate meniscus depinning transitions in confined fluids within semi-infinite capillary slits with asymmetric open edges using both macroscopic theory and classical density functional theory (DFT). We identify four distinct condensed morphologies depending on the pinning state of the meniscus and determine the conditions for transitions between them as functions of the slit geometry and contact angle. Our analysis shows that all depinning transitions are continuous, being second order for partial wetting and third order for complete wetting or drying. Microscopic DFT calculations confirm the predicted phase behavior and reveal important packing and finite-size effects, especially under complete wetting conditions where adsorption layers effectively reduce the accessible slit width. The results provide a systematic description of pinning-depinning phenomena in confined fluids and their dependence on confinement geometry and wetting properties.

• J. Janek, A.O. Parry, A. Malijevský: Multiple Meniscus Depinning Transitions in Open Capillary Slits. J. Phys. Chem. B 129(51), 13325 – 13338, 2026. DOI