# Elastocapillary coiling of an elastic rod inside a drop

## TL;DR

This paper investigates how capillary forces from a liquid drop can induce a straight elastic fiber to coil inside the drop, analyzing equilibrium states, bifurcations, and configurations.

## Contribution

It introduces a theoretical framework for elastocapillary coiling of an elastic rod within a drop, including equilibrium equations and bifurcation analysis.

## Key findings

- Multiple stable configurations of the coiled fiber inside the drop.
- Identification of bifurcation points leading to different configurations.
- Observation of an intermittent regime between 2D and 3D solutions.

## Abstract

Capillary forces acting at the surface of a liquid drop can be strong enough to deform small objects and recent studies have provided several examples of elastic instabilities induced by surface tension. We present such an example where a liquid drop sits on a straight fiber, and we show that the liquid attracts the fiber which thereby coils inside the drop. We derive the equilibrium equations for the system, compute bifurcation curves, and show the packed fiber may adopt several possible configurations inside the drop. We use the energy of the system to discriminate between the different configurations and find a intermittent regime between two-dimensional and three-dimensional solutions as more and more fiber is driven inside the drop.