Movement of active droplets in dense emulsion

Abstract

The motion of a single active droplet and a swarm of droplets in a dense emulsion can differ significantly, which is due to the interaction of the droplets with each other. It has been found that with a decrease in the velocity of active droplets, their motion in a dense emulsion becomes more spatially correlated, and the size of clusters, in which the velocities of the droplets are close, increases. During diffusion motion, active droplets spend most of their time confined in cages and move significant distances after cage rearrangements. With an increase in the average velocity of active droplets in the emulsion, the residence time of the droplets within the cage decreases according to the law ∼u−2. In this case, the mean square displacement of the isolated droplet turns out to be proportional to ∼t3/2. The deviation of the diffusion law of a droplet from the Brownian law is due to the existence of a repulsive force between them.