Speaker
Description
Active particles driven by a chemical reaction are the subject of intense research to date due to their rich physics, being intrinsically far from equilibrium, and their multiple technological applications [1]. Recent attention in the field is now shifting towards exploring the fascinating dynamics of mixture of active and passive systems. In this
talk, I will show different results obtained in my lab on investigating mixture of active and passive particles [2,3]. In particular, we have realized active colloidal rafts,composed of a single catalytic particle encircled by several shells of passive microspheres assembled via light activated, chemophoretic flow [3]. During growth, the rafts display self-propulsion with an average speed that decrease with the raft size. Brownian dynamics simulations that consider only the diffusiophoretic flow reproduce qualitatively the cluster kinetics but fail to explain the cluster propulsion mechanism. Using the Lorenz reciprocal theorem, propulsion emerges by considering hydrodynamics via the diffusiophoretic answer of the substrate to the generated chemophoretic flow.
[1] C. Bechinger, R. Di Leonardo, H. Löwen, C. Reichhardt, G. Volpe, and G. Volpe,
Rev. Mod. Phys. 88, 045006 (2016).
[2] H. Massana-Cid, J. Codina, I. Pagonabarraga, P. Tierno, Proc. Nat. acad. Sci. USA
115, 10618 (2018).
[3] D. Boniface, S. G. Leyva, I. Pagonabarraga, P. Tierno, Nature Communications 15,
5666 (2024).
