Alison E. Patteson (Koser): 0000-0002-4004-1734

Document Type



Winter 12-10-2013




Army Research Office

Funding ID

W911NF-11-1- 0488


We thank Gabriel Redner for helpful discussions and Mike Garcia for early experimental work. This work is supported by the Army Research Office through Grant No. W911NF-11-1-0488.

Official Citation

Koser AE, Keim NC, Arratia PE. Structure and dynamics of self-assembling colloidal monolayers in oscillating magnetic fields. Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Dec;88(6):062304. doi: 10.1103/PhysRevE.88.062304. Epub 2013 Dec 10. PMID: 24483441.




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.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Included in

Physics Commons