Elastocapillary bending of microfibers around liquid droplets

TL;DR

This paper investigates how flexible microfibers bend and wind around liquid droplets due to elastocapillary forces, combining experiments and a minimal elastic beam model to understand the critical conditions for winding.

Contribution

It introduces a minimal elastic beam model to explain elastocapillary bending and winding of microfibers around droplets, supported by experimental validation.

Findings

Fiber bending increases with droplet size.

Winding occurs at a critical droplet size proportional to the elastocapillary length.

The model accurately predicts the winding criterion.

Abstract

We report on the elastocapillary deformation of flexible microfibers in contact with liquid droplets. A fiber is observed to bend more as the size of the contacting droplet is increased. At a critical droplet size, proportional to the bending elastocapillary length, the fiber is seen to spontaneously wind around the droplet. To rationalize these observations, we invoke a minimal model based on elastic beam theory, and find agreement with experimental data. Further energetic considerations provide a consistent prediction for the winding criterion.