Speaker: Dr. Guillaume Duclos

Host: Itamar Kolvin

Title: Instabilities and coarsening in active binary fluids

Abstract:  Interfacial instabilities between immiscible fluids are ubiquitous across scales in nature, appearing in systems ranging from geophysical flows to biological systems. I will present how various aspects of liquid-liquid phase separation are modified when one of the phases is active. I will describe the mechanisms that govern the growth of phase-separated condensates in a self-stirring active fluid, the origin of the non-self-similarity, and of the continuously varying coarsening exponents. I will then turn to active condensates with reduced surface tension, where passive capillary stresses become comparable to the stresses generated by the active phase. In this regime, the active–passive interface deforms, giving rise to morphological instabilities and asymmetric curvature fluctuations. These findings broaden our understanding of phase separation far from equilibrium, with potential implications for materials science and biology.

Bio: Guillaume Duclos is an Assistant Professor of Physics at Brandeis University, where he leads an experimental research group focused on emergent dynamics in active materials. He earned his PhD from the Institut Curie in France, studying the self-organization of biological tissues, and completed his postdoctoral work with Zvonimir Dogic, where he investigated reconstituted active matter systems. His lab explores a range of reconstituted systems composed of energy-consuming proteins, including active fluids, active colloids, and pattern-forming proteins.