Nonequilibrium dynamics of mixtures of active and passive colloidal particles

We develop a mesoscopic field theory for the collective nonequilibrium dynamics of multicomponent mixtures of interacting active (i.e., motile) and passive (i.e., nonmotile) colloidal particles with isometric shape in two spatial dimensions. By a stability analysis of the field theory, we obtain equ...

Authors: Wittkowski, Raphael
Stenhammar, Joakim
Cates, Michael E.
Document types:Article
Media types:Text
Publication date:2017
Date of publication on miami:07.03.2019
Modification date:16.04.2019
Edition statement:[Electronic ed.]
Subjects:active colloidal particles; active-passive mixtures; motility-induced instability; mesoscopic field theory particle-resolved simulations
DDC Subject:530: Physik
License:CC BY 3.0
Language:English
Notes:New Journal of Physics 19 (2017) 105003, 1-16
Funding:Finanziert durch den Open-Access-Publikationsfonds 2017 der Westfälischen Wilhelms-Universität Münster (WWU Münster).
Format:PDF document
URN:urn:nbn:de:hbz:6-85169510228
Permalink:http://nbn-resolving.de/urn:nbn:de:hbz:6-85169510228
Other Identifiers:DOI: 10.1088/1367-2630/aa8195
Digital documents:artikel_wittkowski_2017.pdf

We develop a mesoscopic field theory for the collective nonequilibrium dynamics of multicomponent mixtures of interacting active (i.e., motile) and passive (i.e., nonmotile) colloidal particles with isometric shape in two spatial dimensions. By a stability analysis of the field theory, we obtain equations for the spinodal that describes the onset of a motility-induced instability leading to cluster formation in such mixtures. The prediction for the spinodal is found to be in good agreement with particle-resolved computer simulations. Furthermore, we show that in active-passive mixtures the spinodal instability can be of two different types. One type is associated with a stationary bifurcation and occurs also in one-component active systems, whereas the other type is associated with a Hopf bifurcation and can occur only in active-passive mixtures. Remarkably, the Hopf bifurcation leads to moving clusters. This explains recent results from simulations of active-passive particle mixtures, where moving clusters and interfaces that are not seen in the corresponding one-component systems have been observed.