Structure and dynamics of self-assembling colloidal monolayers in oscillating magnetic fields

Many fascinating phenomena such as large-scale collective flows, enhanced fluid mixing, and pattern formation have been observed in so-called active fluids, which are composed of particles that can absorb energy and dissipate it into the fluid medium. For active particles immersed in liquids, fluid-mediated viscous stresses can play an important role on the emergence of collective behavior. Here, we experimentally investigate their role in the dynamics of self-assembling magnetically driven colloidal particles which can rapidly form organized hexagonal structures. We find that viscous stresses reduce hexagonal ordering, generate smaller clusters, and significantly decrease the rate of cluster formation, all while holding the system at constant number density. Furthermore, we show that time and length scales of cluster formation depend on the Mason number (Mn), or ratio of viscous to magnetic forces, scaling as t ∝ Mn and L ∝ Mn-1/2. Our results suggest that viscous stresses hinder collective behavior in a self-assembling colloidal system.

© American Physical Society (APS) [Structure and dynamics of self-assembling colloidal monolayers in oscillating magnetic fields. Physical Review E 88, 6 (2013)]

Files

Metadata

Work Title Structure and dynamics of self-assembling colloidal monolayers in oscillating magnetic fields
Access
Open Access
Creators
  1. Alison E. Koser
  2. Nathan C. Keim
  3. Paulo E. Arratia
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Physical Review E
Publication Date December 10, 2013
Publisher Identifier (DOI)
  1. https://doi.org/10.1103/PhysRevE.88.062304
Deposited January 23, 2024

Versions

Analytics

Collections

This resource is currently not in any collection.

Work History

Version 1
published

  • Created
  • Added 1311.4497-1.pdf
  • Added Creator Alison E. Koser
  • Added Creator Nathan C. Keim
  • Added Creator Paulo E. Arratia
  • Published
  • Updated Description Show Changes
    Description
    • Many fascinating phenomena such as large-scale collective flows, enhanced fluid mixing, and pattern formation have been observed in so-called active fluids, which are composed of particles that can absorb energy and dissipate it into the fluid medium. For active particles immersed in liquids, fluid-mediated viscous stresses can play an important role on the emergence of collective behavior. Here, we experimentally investigate their role in the dynamics of self-assembling magnetically driven colloidal particles which can rapidly form organized hexagonal structures. We find that viscous stresses reduce hexagonal ordering, generate smaller clusters, and significantly decrease the rate of cluster formation, all while holding the system at constant number density. Furthermore, we show that time and length scales of cluster formation depend on the Mason number (Mn), or ratio of viscous to magnetic forces, scaling as tâ̂Mn and Lâ̂Mn<sup>-</sup>1<sup>/</sup>2. Our results suggest that viscous stresses hinder collective behavior in a self-assembling colloidal system.
    • Many fascinating phenomena such as large-scale collective flows, enhanced fluid mixing, and pattern formation have been observed in so-called active fluids, which are composed of particles that can absorb energy and dissipate it into the fluid medium. For active particles immersed in liquids, fluid-mediated viscous stresses can play an important role on the emergence of collective behavior. Here, we experimentally investigate their role in the dynamics of self-assembling magnetically driven colloidal particles which can rapidly form organized hexagonal structures. We find that viscous stresses reduce hexagonal ordering, generate smaller clusters, and significantly decrease the rate of cluster formation, all while holding the system at constant number density. Furthermore, we show that time and length scales of cluster formation depend on the Mason number (Mn), or ratio of viscous to magnetic forces, scaling as tMn and LMn<sup>-</sup>1<sup>/</sup>2. Our results suggest that viscous stresses hinder collective behavior in a self-assembling colloidal system.
  • Updated