M. Cristina Marchetti, Ph.D.,
University of California, Santa Barbara
Topic: Interfacial properties of active fluids
Abstract: There are many situations where active fluids coexist with passive ones. In bacterial swarms, internal boundaries form separating cells of different types or separating live and dead cells. In cell biology, the evidence for the formation of membrane-less organelles has fueled interest in the role of active processes in liquid-liquid phase separation. Inspired by recent experiments that combine a microtubule-based active fluid with an immiscible binary polymer mixture, we have used numerical and analytical methods to explore how active stresses and associated active flows in a bulk active fluid modify the properties of the soft interfaces in a phase separating mixture. Experiments and theory have revealed a wealth of intriguing phenomena, including giant interfacial fluctuation, traveling interfacial waves, activity suppressed phase separation, and activity controlled wetting transitions.