Speaker
Description
A frequent experimental realization of a microswimmer relies on self-chemophoresis. Chemophoresis (also called diffusiophoresis) denotes the motion of a particle immersed in a fluid solution due to a composition gradient. And self-chemophoresis pertains to the case that the gradient is generated by the particle itself through catalytic activity on its surface.
Conceptually one can write "phoretic velocity = phoretic coefficient x chemical gradient". In the "classic picture" of chemophoresis, the phoretic coefficient follows from linear response theory and the paradigm that "self-phoresis is normal phoresis but in a self-generated gradient" is usually invoked. We have shown, however, that this may not be the case because the activity of the particle can also affects the phoretic coefficient significantly, thus providing an alternative mechanism for self-propulsion.
We also predict that, in the apparently unrelated system of an intruder inmersed in a shaken granular bath, the intruder will self-propel according to this new mechanism. This unexpected connection will be discussed, with a focus on the complementarity between the two scenarios.
