Surface roughness stabilizes the clustering of self-propelled triangles

Sven Erik Ilse, Christian Holm, Joost de Graaf*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Self-propelled particles can spontaneously form dense phases from a dilute suspension in a process referred to as motility-induced phase separation. The properties of the out-of-equilibrium structures that are formed are governed by the specifics of the particle interactions and the strength of the activity. Thus far, most studies into the formation of these structures have focused on spherical colloids, dumbbells, and rod-like particles endowed with various interaction potentials. Only a few studies have examined the collective behavior of more complex particle shapes. Here, we increase the geometric complexity and use molecular dynamics simulations to consider the structures formed by triangular self-propelled particles with surface roughness. These triangles either move towards their apex or towards their base, i.e., they possess a polarity. We find that apex-directed triangles cluster more readily, more stably, and have a smoother cluster interface than their base-directed counterparts. A difference between the two polarities is in line with the results of Wensink et al. [Phys. Rev. E 89, 010302 (2014)]; however, we obtain the reversed result when it comes to clustering, namely, that apex-directed triangles cluster more successfully. We further show that reducing the surface roughness negatively impacts the stability of the base-directed structures, suggesting that their formation is in large part due to surface roughness. Our results lay a solid foundation for future experimental and computational studies into the effect of roughness on the collective dynamics of swimmers. Published by AIP Publishing.

Original languageEnglish
Article number134904
Number of pages13
JournalThe Journal of Chemical Physics
Volume145
Issue number13
DOIs
Publication statusPublished - 7 Oct 2016

Keywords

  • CATALYTIC NANOMOTORS
  • COLLOIDAL PARTICLES
  • JANUS SWIMMERS
  • SPERM CELLS
  • DYNAMICS
  • PHASE
  • HYDRODYNAMICS
  • MATTER
  • MICROMOTORS
  • SUSPENSIONS

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