  Rheotaxis is a well-known phenomenon among microbial organisms and artificial
active colloids, wherein the swimmers respond to an imposed flow. We report the
first experimental evidence of upstream rheotaxis by spherical active droplets.
It is shown that the presence of a nearby wall and the resulting strong
flow-gradient at the droplet level is at the root of this phenomenon.
Experiments with optical cells of different heights reveal that rheotaxis is
observed only for a finite range of shear rates, independent of the bulk
flow-rate. We conjecture that the flow induced distortion of an otherwise
isotropic distribution of filled/empty micelles around the droplet propels it
against the flow. We also show that nematic droplets exhibit elastic
stress-induced oscillations during their rheotactic flight. A promising
potential of manipulating the rheotactic behavior to trap as well as shuttle
droplets between target locations is demonstrated, paving way to potentially
significant advancement in bio-medical applications.
