Nucleation pathway and kinetics of phase-separating active Brownian particles. Issue 24 (29th April 2016)

• Record Type: Journal Article
• Authors: Richard, David; Löwen, Hartmut; Speck, Thomas
• Is Part Of: Soft matter. Volume 12:Issue 24(2016)
• Page Start: 5257
• Page End: 5264
• Publication Date: 2016-04-29
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c6sm00485g
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : Suspensions of purely repulsive but self-propelled Brownian particles might undergo phase separation, a phenomenon that strongly resembles the phase separation of passive particles with attractions. Here we show that active Brownian particles exhibit the same qualitative behavior for the nucleation kinetics as in the case of the classical liquid–vapor, first-order transition, and we reveal the importance of the radial polarization for small clusters to correctly describe the reactive path. Abstract : Suspensions of purely repulsive but self-propelled Brownian particles might undergo phase separation, a phenomenon that strongly resembles the phase separation of passive particles with attractions. Here we employ computer simulations to study the nucleation kinetics and the microscopic pathway active Brownian disks take in two dimensions when quenched from the homogeneous suspension to propulsion speeds beyond the binodal. We find the same qualitative behavior for the nucleation rate as a function of density as for a passive suspension undergoing liquid–vapor separation, suggesting that the scenario of an effective free energy also extends to the kinetics of phase separation. We study the transition in more detail through a committor analysis and find that transition states are best described by a combination of cluster size and the radial polarization of particles in the cluster.