A slender thread of elastic hydrogel is susceptible to a surface instability that is reminiscent of the classical Rayleigh–Plateau instability of liquid jets. The final, highly nonlinear states that are observed in experiments arise from a competition between capillarity and large elastic deformations. Combining a slender analysis and fully three-dimensional numerical simulations, we present the phase map of all possible morphologies for an unstable neo-Hookean cylinder subjected to capillary forces. Interestingly, for softer cylinders we find the coexistence of two distinct configurations, namely, cylinders-on-a-string and beads-on-a-string. It is shown that for a given set of parameters, the final pattern is selected via a dynamical evolution. To capture this, we compute the dispersion relation and determine the characteristic wavelength of the dynamically selected profiles. The validity of the “slender” results is confirmed via simulations and these results are consistent with experiments on elastic and viscoelastic threads.
Bibliographical noteFunding Information:
A. P. and M. K. equally contributed to this work. M. K. and J. H. S. acknowledges support from NWO through VICI Grant No. 680-47-632, and A. P. from European Research Council (ERC) Consolidator Grant No. 616918. J. E. acknowledges the support of Leverhulme Trust International Academic Fellowship IAF-2017-010. M. A. H. thanks the Ministerio de Economia y Competitividad and the Junta de Andalucia for partial support under the Projects No. PID2019-108278-RB-C31 and No. PAIDI: P18-FR-3623 respectively.
© The Royal Society of Chemistry.