Jerome Delhomelle Abstract

Title: Microswimmers under the spotlight: Orchestrating assembly and motion in active matter

Abstract: 

The ability of active matter to assemble into reconfigurable nonequilibrium structures has drawn considerable interest in recent years. We investigate how active fluids respond to spatial light patterns through simulations and experiments on light-activated self-propelled colloidal particles. We examine the processes of inverse templated assembly, which involves creating a region without active particles through a bright pattern, and templated assembly, which promotes the formation of dense particle regions through a dark pattern. We identify scaling relations for the characteristic times for both processes and quantify the interplay between the dimension of the applied pattern and the intrinsic properties of the active fluid. We also explore the assembly mechanism and dynamics of large clusters and show how we can direct their motion via dynamic light patterns. The protocols developed here open the door to arbitrarily precise and programmable nonequilibrium assembly and motion in active matter.