Capillary Interfacial Tension in Active Phase Separation

Fausti, G.; Tjhung, E.; Cates, M. E.; Nardini, C.

Abstract

In passive fluid-fluid phase separation, a single interfacial tension sets both the capillary fluctuations of the interface and the rate of Ostwald ripening. We show that these phenomena are governed by two different tensions in active systems, and compute the capillary tension σ cw which sets the relaxation rate of interfacial fluctuations in accordance with capillary wave theory. We discover that strong enough activity can cause negative σ cw . In this regime, depending on the global composition, the system self-organizes, either into a microphase-separated state in which coalescence is highly inhibited, or into an “active foam” state. Our results are obtained for Active Model B + , a minimal continuum model which, although generic, admits significant analytical progress.

Citation

Fausti, G., Tjhung, E., Cates, M., & Nardini, C. (2021). Capillary Interfacial Tension in Active Phase Separation. Physical Review Letters, 127(6), Article 068001. https://doi.org/10.1103/physrevlett.127.068001

• Journal Article Type: Article
• Acceptance Date: Jul 2, 2021
• Online Publication Date: Aug 3, 2021
• Publication Date: Aug 6, 2021
• Deposit Date: Nov 8, 2021
• Publicly Available Date: Nov 8, 2021
• Journal: Physical Review Letters
• Print ISSN: 0031-9007
• Electronic ISSN: 1079-7114
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 127
• Issue: 6
• Article Number: 068001
• DOI: https://doi.org/10.1103/physrevlett.127.068001
• Public URL: https://durham-repository.worktribe.com/output/1222857