Elastocapillary Coiling of an Elastic Rod Inside a Drop


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.

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We thank Camille Dianoux and Sinan Haliyo for their help on microscopy, and Arnaud Antkowiak for comments on the variational approach. The present work was supported by ANR grant ANR-09-JCJC-0022-01, ANR-14-CE07-0023-01, and ANR-13-JS09-0009. Financial support from ‘La Ville de Paris—Programme Émergence’ and CNRS, through a PEPS-PTI grant, is also gratefully acknowledged.

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Correspondence to Sébastien Neukirch.

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Elettro, H., Grandgeorge, P. & Neukirch, S. Elastocapillary Coiling of an Elastic Rod Inside a Drop. J Elast 127, 235–247 (2017). https://doi.org/10.1007/s10659-016-9611-4

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  • Capillarity
  • Bifurcation
  • Packing

Mathematics Subject Classification

  • 74K10
  • 74F10
  • 74G65