Active Drops
In collaboration with the group "Micro, Nano. and Molecular Systems Lab" of Prof. P. Fischer at the MPI-IS and with Prof. A. Dominguez (Univ. of Seville), the behavior of a sessile drop containing active particles with negligible self-propulsion was investigated. For particle-density above a certain threshold, a symmetry breaking transition to collective motion of particles and self-organized flow patterns within the drop is observed. This emerges through a novel mechanism that involves an interplay between the chemical-activity-induced Marangoni stresses at the liquid–liquid interface and the geometrical confinement (by the drop). In ensembles of such active drops long-ranged ordering of the flow patterns within the drops is observed.
D.P.Singh, A. Dominguez, U. Choudhury, S.N. Kottapalli, M.N. Popescu, S. Dietrich, and P. Fischer, Interface-mediated spontaneous symmetry breaking and mutual communication between drops containing chemically active particles, Nature Commun. 11, 2210 (2020)