Swimming in a crystal

Aidan T Brown , Ioana D Vladescu , Angela Dawson , Teun Vissers , Jana Schwarz-Linek (1) , Juho S. Lintuvuori (2) , Wilson Ck Poon

1 SUPA, School of Physics and Astronomy
2 LPS - Laboratoire de Physique des Solides

We study catalytic Janus particles and Escherichia coli bacteria swimming in a two-dimensional colloidal crystal. The Janus particles orbit individual colloids and hop between colloids stochastically, with a hopping rate that varies inversely with fuel (hydrogen peroxide) concentration. At high fuel concentration, these orbits are stable for 100s of revolutions, and the orbital speed oscillates periodically as a result of hydrodynamic, and possibly also phoretic, interactions between the swimmer and the six neighbouring colloids. Motile E. coli bacteria behave very differently in the same colloidal crystal: their circular orbits on plain glass are rectified into long, straight runs, because the bacteria are unable to turn corners inside the crystal.

Domaines: Matière Molle [cond-mat.soft]

Aidan T Brown, Ioana D Vladescu, Angela Dawson, Teun Vissers, Jana Schwarz-Linek, et al.. Swimming in a crystal. Soft Matter, 2016, 12 (1), pp.131-140. ⟨10.1039/c5sm01831e⟩. ⟨hal-01540513⟩