Mechanisms of dynamic wetting failure in the presence of soluble surfactants

Chen Yu Liu, Marcio S. Carvalho, Satish Kumar

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


A hydrodynamic model and flow visualization experiments are used to understand the mechanisms through which soluble surfactants can influence the onset of dynamic wetting failure. In the model, a Newtonian liquid displaces air in a rectangular channel in the absence of inertia. A Navier-slip boundary condition and constant contact angle are used to describe the dynamic contact line, and surfactants are allowed to adsorb to the interface and moving channel wall (substrate). The Galerkin finite element method is used to calculate steady states and identify the critical capillary number Cacrit at which wetting failure occurs. It is found that surfactant solubility weakens the influence of Marangoni stresses, which tend to promote the onset of wetting failure. Adsorption of surfactants to the substrate can delay the onset of wetting failure due to the emergence of Marangoni stresses that thicken the air film near the dynamic contact line. The experiments indicate that Cacrit increases with surfactant concentration. For the more viscous solutions used, this behaviour can largely be explained by accounting for changes to the mean surface tension and static contact angle produced by surfactants. For the lowest-viscosity solution used, comparison between the model predictions and experimental observations suggests that other surfactant-induced phenomena such as Marangoni stresses may play a more important role.

Original languageEnglish (US)
Pages (from-to)677-703
Number of pages27
JournalJournal of Fluid Mechanics
StatePublished - Aug 25 2017

Bibliographical note

Publisher Copyright:
© 2017 Cambridge University Press.


  • coating
  • contact lines
  • interfacial flows (free surface)


Dive into the research topics of 'Mechanisms of dynamic wetting failure in the presence of soluble surfactants'. Together they form a unique fingerprint.

Cite this