Stratification Dynamics in Drying Colloidal Mixtures

Michael P. Howard, Arash Nikoubashman, Athanassios Z. Panagiotopoulos

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Stratification in binary colloidal mixtures was investigated using implicit-solvent molecular dynamics simulations. For large particle size ratios and film Péclet numbers greater than unity, smaller colloids migrated to the top of the film, while big colloids were pushed to the bottom, creating an "inverted" stratification. This peculiar behavior was observed in recent simulations and experiments conducted by Fortini et al. [Phys. Rev. Lett. 2016, 116, 118301]. To rationalize this behavior, particle size ratios and drying rates spanning qualitatively different Péclet number regimes were systematically studied, and the dynamics of the inverted stratification were quantified in detail. The stratified layer of small colloids was found to grow faster and to larger thicknesses for larger size ratios. Interestingly, inverted stratification was observed even at moderate drying rates where the film Péclet numbers were comparable to unity, but the thickness of the stratified layer decreased. A model based on dynamical density functional theory is proposed to explain the observed phenomena.

Original languageEnglish (US)
Pages (from-to)3685-3693
Number of pages9
JournalLangmuir
Volume33
Issue number15
DOIs
StatePublished - Apr 18 2017

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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