Active Emulsion droplet arrays

Stabilized emulsions containing the oscillating Belousov - Zhabotinsky chemical reaction (BZ) show interesting dynamics. Each drop acts as an independent chemical clock. However, they chemically communicate and exhibit collective behavior. In (a) six BZ drops are contained in a  capillary tube. The  white bars are light, which set the oscillators in the reduced state. Drops 1 & 6 are always exposed to light, setting the boundary conditions. Drops 3 & 4 are exposed to light for 0.5 periods. (b) A space time plot of the oscillations. White corresponds to the oxidized state; black to reduced. The drops adopt a dynamic oscillatory state predicted by theory. (c,d) Photograph and schematic, respectively, of experimental set-up. Study of these systems will elucidate a variety of chemically dynamic systems, ranging from neurons to Active Matter – polymeric systems which can convert chemical energy to mechanical motion.

The BZ reaction serves as the paradigm for non-linear chemical oscillators. Oscillating chemical cycles are essential components of much of biology, including the function of neurons and neural networks as well as for cell division and other cyclic and circadian  rhythms. Our goal is to characterize the dynamical behavior of these BZ emulsions and model their behavior. Because we can control many aspects of the individual oscillators and the degree of coupling, we believe this work will serve as a model system for interacting chemical oscillators.