Activity-Induced Phase Separation and Self-Assembly in Mixtures of Active and Passive Particles

Joakim Stenhammar*, Raphael Wittkowski, Davide Marenduzzo, Michael E. Cates

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the phase behavior and kinetics of a monodisperse mixture of active (i.e., self-propelled) and passive isometric Brownian particles through Brownian dynamics simulations and theory. As in a purely active system, motility of the active component triggers phase separation into a dense and a dilute phase; in the dense phase, we further find active-passive segregation, with “rafts” of passive particles in a “sea” of active particles. We find that phase separation from an initially disordered mixture can occur with as little as 15% of the particles being active. Finally, we show that a system prepared in a suitable fully segregated initial state reproducibly self-assembles an active “corona,” which triggers crystallization of the passive core by initiating a compression wave. Our findings are relevant to the experimental pursuit of directed self-assembly using active particles.

Original languageEnglish
Article number018301
Number of pages5
JournalPhysical Review Letters
Volume114
Issue number1
DOIs
Publication statusPublished - 6 Jan 2015

Keywords

  • BROWNIAN PARTICLES
  • SEGREGATION
  • MOTILITY
  • DISKS

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