Active colloids in complex fluids

Alison E. Patteson, Arvind Gopinath, Paulo E. Arratia

Research output: Contribution to journalReview articlepeer-review

90 Scopus citations


We review recent work on active colloids or swimmers, such as self-propelled microorganisms, phoretic colloidal particles, and artificial micro-robotic systems, moving in fluid-like environments. These environments can be water-like and Newtonian but can frequently contain macromolecules, flexible polymers, soft cells, or hard particles, which impart complex, nonlinear rheological features to the fluid. While significant progress has been made on understanding how active colloids move and interact in Newtonian fluids, little is known on how active colloids behave in complex and non-Newtonian fluids. An emerging literature is starting to show how fluid rheology can dramatically change the gaits and speeds of individual swimmers. Simultaneously, a moving swimmer induces time dependent, three dimensional fluid flows that can modify the medium (fluid) rheological properties. This two-way, non-linear coupling at microscopic scales has profound implications at meso- and macro-scales: steady state suspension properties, emergent collective behavior, and transport of passive tracer particles. Recent exciting theoretical results and current debate on quantifying these complex active fluids highlight the need for conceptually simple experiments to guide our understanding.

Original languageEnglish (US)
Pages (from-to)86-96
Number of pages11
JournalCurrent Opinion in Colloid and Interface Science
StatePublished - Feb 1 2016
Externally publishedYes


  • Active matter
  • Bacterial suspensions
  • Colloids
  • Complex fluids
  • Self-propulsion

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Colloid and Surface Chemistry


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