Continuous and discontinuous morphological transitions between capillary bridges on a beaded chain pulled out from a liquid

TL;DR

This study combines theoretical analysis and experiments to investigate how capillary bridges form and transition between different types when pulling a beaded chain from a liquid, revealing both continuous and discontinuous morphological phase transitions.

Contribution

It provides the first detailed description and validation of the mechanisms behind capillary bridge formation and their morphological transitions during chain extraction from a liquid.

Findings

Transition type depends on bead size relative to capillary length.

Continuous transition occurs for beads larger than the capillary length.

Discontinuous transition occurs for smaller beads, affecting capillary forces.

Abstract

We describe theoretically and validate experimentally the mechanism of formation of capillary bridges during pulling a beaded chain out from a liquid with a planar surface. There are two types of capillary bridges present in this system, namely the sphere-planar liquid surface bridge initially formed between the spherical bead leaving the liquid bath and the original bulk planar liquid surface, and the sphere-sphere capillary bridge formed between neighbouring beads in the part of the chain above the liquid surface. During pulling the chain out of the liquid, the sphere-planar liquid surface bridge transforms into the sphere-sphere bridge. We show that for monodisperse spherical beads comprising the chain, this morphological phase transition can be either continuous or discontinuous. The transition is continuous when the diameter of the spherical beads is larger than the capillary length. Otherwise, the transition is discontinuous, likewise the capillary force acting on the chain.