Self-propulsion of chemically-active droplets in a cylindrical capillary

Chemically-active droplets swim spontaneously  by exchanging chemical solutes with their environment and exploiting the non-linear coupling of their transport to the surface-generated flows created by their gradients. They always propel near boundaries, an experimental feature that was observed to significantly impact their dynamics.

Here, we present a novel numerical framework based on moving embedded boundaries to analyse the nonlinear self-propulsion dynamics of chemically-active droplets in complex spatial configuration. We  further use that framework to study the self-propulsion of an active droplet along a capillary tube, focusing specifically on the impact of the confinement intensity (i.e. the particle-to-tube radius ratio) on the dynamics and propulsion characteristics.