Interface-mediated spontaneous symmetry breaking and mutual communication between drops containing chemically active particles

2020

Article

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Symmetry breaking and the emergence of self-organized patterns is the hallmark of com- plexity. Here, we demonstrate that a sessile drop, containing titania powder particles with negligible self-propulsion, exhibits a transition to collective motion leading to self-organized flow patterns. This phenomenology emerges through a novel mechanism involving the interplay between the chemical activity of the photocatalytic particles, which induces Mar- angoni stresses at the liquid–liquid interface, and the geometrical confinement provided by the drop. The response of the interface to the chemical activity of the particles is the source of a significantly amplified hydrodynamic flow within the drop, which moves the particles. Furthermore, in ensembles of such active drops long-ranged ordering of the flow patterns within the drops is observed. We show that the ordering is dictated by a chemical com- munication between drops, i.e., an alignment of the flow patterns is induced by the gradients of the chemicals emanating from the active particles, rather than by hydrodynamic interactions.

@article{2020Singh,
  title = {Interface-mediated spontaneous symmetry breaking and mutual communication between drops containing chemically active particles},
  author = {Singh, D. P. and Domínguez, A. and Choudhury, U. and Kottapalli, S. N. and Popescu, M. N. and Dietrich, S. and Fischer, P.},
  journal = {Nature Communications},
  volume = {11},
  pages = {2210},
  month = may,
  year = {2020},
  doi = {10.1038/s41467-020-15713-y},
  url = {https://www.nature.com/articles/s41467-020-15713-y},
  month_numeric = {5}
}