Bioinspired Plateau–Rayleigh Instability on Fibers: From Droplets Manipulation to Continuous Liquid Films

Abstract

The Plateau–Rayleigh instability (PRI) of a liquid column, which always spontaneously breaks into droplets to minimize surface energy, underlies a variety of fascinating phenomena in daily life and industrial applications. Different from the free liquid column, the evolution of the liquid film on a fiber involves solid‐liquid interfaces which allow for regulating the PRI. Recently, natural fibers with certain topologies have witnessed various dynamic liquid behaviors from droplet manipulation to continuous liquid films. Tailoring the topology of local curved liquid film by the structural‐confinement is the key to manipulating liquids, where the asymmetric Laplace pressure generated by the asymmetric/non‐spherical liquid film promotes the liquid motion. In nature, the spider silk collects droplets efficiently by the spindle‐knot structure; while the mulberry silk enables a smooth surface‐coating on dual‐parallel fibers. Drawing inspirations, many artificial structured fibers are developed to precisely regulate liquid behaviors in the form of either separated droplets or continuous liquid films, which have demonstrated applications as fluidic coating, micro‐patterning, and materials fabrication. Here, recent research progress on bioinspired fibrous PRI from the viewpoints of tailoring the Laplace pressure by rationally designing the surface topology, which offers inspiration for liquid manipulation using open fibrous media, is reviewed.