Spontaneous dispersion of particles on liquid surfaces

Pushpendra Singh, Daniel D. Joseph, Sathish K. Gurupatham, Bhavin Dalal, Sai Nudurupati

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


When small particles (e.g., flour, pollen, etc.) come in contact with a liquid surface, they immediately disperse. The dispersion can occur so quickly that it appears explosive, especially for small particles on the surface of mobile liquids like water. This explosive dispersion is the consequence of capillary force pulling particles into the interface causing them to accelerate to a relatively large velocity. The maximum velocity increases with decreasing particle size; for nanometer-sized particles (e.g., viruses and proteins), the velocity on an air-water interface can be as large as ≈47 m/s. We also show that particles oscillate at a relatively high frequency about their floating equilibrium before coming to stop under viscous drag. The observed dispersion is a result of strong repulsive hydrodynamic forces that arise because of these oscillations.

Original languageEnglish (US)
Pages (from-to)19761-19764
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number47
StatePublished - Nov 24 2009

All Science Journal Classification (ASJC) codes

  • General


  • Adsorption
  • Capillarity
  • Fluid-fluid interfaces
  • Monolayers


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