Active droploids

Abstract

Active matter comprises self-driven units, such as bacteria and synthetic microswimmers, that can spontaneously form complex patterns and assemble into functional microdevices. These processes are possible thanks to the out-of-equilibrium nature of active-matter systems, fueled by a one-way free-energy flow from the environment into the system. Here, we take the next step in the evolution of active matter by realizing a two-way coupling between active particles and their environment, where active particles act back on the environment giving rise to the formation of superstructures. In experiments and simulations we observe that, under light-illumination, colloidal particles and their near-critical environment create mutually-coupled co-evolving structures. These structures unify in the form of active superstructures featuring a droplet shape and a colloidal engine inducing self-propulsion. We call them active droploids—a portmanteau of droplet and colloids. Our results provide a pathway to create active superstructures through environmental feedback.

Spontaneous chiral symmetry breaking in a random driven chemical system

“…For instance, a photoactivated reaction may lead to precipitates that block light input and inhibit further reaction i.e., a state-dependent, environmental effect. Indeed, environmental feedback can induce pattern formation and has recently been shown to drive the emergence of phase-separated, active droplets systems 29 , 30 .…”

Spontaneous Chiral Symmetry Breaking in a Random Driven Chemical System

“…Indeed, environmental feedback can induce pattern formation and has recently been shown to drive the emergence of phase-separated, active droplets systems. 29,30…”

“…Indeed, environmental feedback can induce pattern formation and has recently been shown to drive the emergence of phase-separated, active droplets systems. 29,30 Lastly, due to the chiral composition of each channel, forces are functionally identical but mirrored, i.e., they are related through a corresponding R/S label swap in the expression as {A i , R k , S j } ←→ {A i , S k , R j }. This ensures the system is kept symmetric and allows us to deduce the emergence of any diverging dynamics as the result of chiral symmetry breaking and not a prescribed environmental bias.…”

Motorisierte Tröpfchen

“…Damit verändern nicht nur die Teilchen ihre lokale Umgebung, auch die so entstandene Blase wirkt auf die Teilchen selbst zurück; und somit schließt sich eine Rückkopplungschleife. Diese erzeugt hierüber neuartige Superstrukturen von aktiven Tröpfchen mit einem selbstorganisierten kolloidalen Motor [2], die wir „Droploids“ getauft haben.…”