Self-propulsion and interaction of chemically-active droplets
Chemically-active droplets slowly solubilizing in a surfactant-
laden solution can self-propel spontaneously as a result of the non-linear
transport of surfactant molecules and micellar compounds by thesolute-induced
interfacial flows. Many recent experiments have reported the intriguing
individual behaviour of these droplets. Furthermore, such droplets are
fundamentally anti-chemotactic : they avoid regions of solute accumulation
such as their own chemical trail and the vicinity of other droplets or
confining walls. In experiments on multiple-droplet interactions, this results
in complex avoiding trajectories. Motivated by these observations, we use
theoretical modeling and numerical simulations to rationalise these individual
and collective dynamics. In this presentation, I will discuss our recent work
on the nonlinear interplay of hydrodynamic and chemical interactions in
droplet collisions or self-propulsion in confined environments. In particular,
based on the analysis of the complete hydro-chemical interactions in a two-
droplet collision, I will show how such pairwise collisions may lead to the
emergence of a variety of collective dynamical regimes, as well as alignment
and scattering of the droplets.
