Elastocapillary Snapping: Capillarity Induces Snap-Through Instabilities in Small Elastic Beams

TL;DR

This paper explores how small water droplets and bubbles can induce snap-through instabilities in elastic beams, revealing new insights into elastocapillarity with potential applications in miniaturization.

Contribution

It provides experimental and theoretical analysis of capillary-induced snapping in elastic beams, demonstrating its occurrence across different scales and conditions.

Findings

Capillary forces can trigger snap-through in millimeter and centimeter-sized elastic beams.

Snapping can oppose gravity or be initiated by soap bubbles.

A condensation-induced version of the experiment is proposed for miniaturization.

Abstract

We report on the capillary-induced snapping of elastic beams. We show that a millimeter-sized water drop gently deposited on a thin buckled polymer strip may trigger an elastocapillary snap-through instability. We investigate experimentally and theoretically the statics and dynamics of this phenomenon and we further demonstrate that snapping can act against gravity, or be induced by soap bubbles on centimeter-sized thin metal strips. We argue that this phenomenon is suitable to miniaturization and design a condensation-induced spin-off version of the experiment involving an hydrophilic strip placed in a steam flow.