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  • Open Access

Fluid Flow and Spatiotemporal Chaos in Chemically Active Emulsions

Charu Datt1,2,*, Jonathan Bauermann1,3, Nazmi Burak Budanur1, and Frank Jülicher1,4,5

  • *Contact author: charudatt@mech.keio.ac.jp
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Phys. Rev. Lett. 136, 254001 – Published 24 June, 2026

DOI: https://doi.org/10.1103/z1hs-ydjc

Abstract

We study phase-separating fluid mixtures as they demix in the presence of chemical reactions that maintain them away from thermodynamic equilibrium. We show that in such chemically active emulsions the interplay of chemical reactions, phase separation, and hydrodynamics effects complex self-organization and pattern formation that can give rise to spatiotemporal chaos. This chaotic dynamics, unlike in classical turbulence, is not due to fluid inertia—we analyze the system in the Stokes flow regime—and it is different from the turbulence of active nematics at low Reynolds number, for our fluid mixtures lack any orientational order. To explore the generic features of nonlinear dynamics in our system, we derive amplitude equations which we find to be identical to those obtained for Rayleigh-Benard convection with mean flow and stress-free conditions at the top and bottom plates. Chemically active emulsions possessing no internal order, we thus establish, can exhibit chaoticity that is driven by interfacial stresses in the fluid mixture.

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Phys. Rev. Lett. 136, 254001– Published 24 June, 2026
  • Received 18 September 2025
  • Accepted 6 May 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Open access publication funded by the Max Planck Society.

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