Unconventional phase separation kinetics of colloids in active liquids

Abstract

Phase ordering driven by nonequilibrium fluctuations is a hallmark of both living and synthetic active matter. Unlike equilibrium systems, where ordered states arise from the minimisation of free energy, active systems are fueled by the constant injection of energy at the microscopic scale. The emergence of ordered phases in such driven systems challenges our conventional views of domain growth and interfacial structure. In this talk, I will present results on the investigation of coarsening of colloidal clusters in active liquids containing E. coli, highlighting the nature of ordering in systems dominated by strong fluctuations. Our experiments reveal that uniform dispersions of colloids and swimmers are inherently unstable, resulting in spontaneous phase separation characterised by fractal interfaces and unconventional domain growth kinetics.