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DOE OSTI · 2480745

Asymmetric fluctuations and self-folding of active interfaces

Zhao, Liang [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0009000681387535)·Gulati, Paarth [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0009000214868831)·Caballero, Fernando [Univ. of California, Santa Barbara, CA (United States); Brandeis Univ., Waltham, MA (United States)] (ORCID:0000000308072087)·Kolvin, Itamar [Univ. of California, Santa Barbara, CA (United States); Georgia Institute of Technology, Atlanta, GA (United States)] (ORCID:0000000268691245)·Adkins, Raymond [Univ. of California, Santa Barbara, CA (United States); Yale Univ., New Haven, CT (United States)] (ORCID:0000000176222812)·Marchetti, M. Cristina [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0000000335834999)·Dogic, Zvonimir [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0000000301421838)
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Abstract

We study the structure and dynamics of the interface separating a passive fluid from a microtubule-based active fluid. Turbulent-like active flows power giant interfacial fluctuations, which exhibit pronounced asymmetry between regions of positive and negative curvature. Experiments, numerical simulations, and theoretical arguments reveal how the interface breaks up the spatial symmetry of the fundamental bend instability to generate local vortical flows that lead to asymmetric interface fluctuations. The magnitude of interface deformations increases with activity: In the high activity limit, the interface self-folds invaginating passive droplets and generating a foam-like phase, where active fluid is perforated with passive droplets. These results demonstrate how active stresses control the structure, dynamics, and break-up of soft, deformable, and reconfigurable liquid–liquid interfaces.

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Zhao, Liang [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0009000681387535), Gulati, Paarth [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0009000214868831), Caballero, Fernando [Univ. of California, Santa Barbara, CA (United States); Brandeis Univ., Waltham, MA (United States)] (ORCID:0000000308072087), Kolvin, Itamar [Univ. of California, Santa Barbara, CA (United States); Georgia Institute of Technology, Atlanta, GA (United States)] (ORCID:0000000268691245), Adkins, Raymond [Univ. of California, Santa Barbara, CA (United States); Yale Univ., New Haven, CT (United States)] (ORCID:0000000176222812), Marchetti, M. Cristina [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0000000335834999), Dogic, Zvonimir [Univ. of California, Santa Barbara, CA (United States)] (ORCID:0000000301421838). 2024-12-10. Asymmetric fluctuations and self-folding of active interfaces. https://doi.org/10.1073/pnas.2410345121

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