(572b) Chemotactic Motility-Induced Phase Separation

In the past decade, extensive research has elucidated the mechanism and generalized thermodynamics of motility-induced phase separation (MIPS), where randomly oriented and self-propelled agents known as active Brownian particles separate into dilute and dense phases. However, it is unclear how chemotaxis, a directed motion along a chemical gradient, can affect MIPS—despite its ubiquity in many biological systems such as microbes, eukaryotic cells, and even enzymes, as well as synthetic forms of active matter such as chemically-responsive colloids and robots. Here, we use continuum and particle-based models to study chemotactic MIPS. We find that chemotaxis can dramatically suppress MIPS, arrest coarsening, and lead to the emergence of a fascinating array of oscillatory patterns. These results therefore expand our understanding of the rich phenomenology of MIPS.