Numerical investigation of the effect of insoluble surfactant on drop formation in microfluidic device
1 Department of Mechanical Engineering, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands
2 Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands
a e-mail: P.D.Anderson@tue.nl
Revised: 23 April 2013
Published online: 17 June 2013
Surfactants are commonly used in droplet-based microfluidics to stabilize the droplet interface. In this study, we investigate the effect of insoluble surfactant on drop formation in a capillary microfluidic device. We use a diffuse-interface method to describe the evolution of interface involving insoluble surfactant. The Navier-Stokes/Cahn-Hilliard equations and the surfactant conservation equation are solved by a finite element method along with a grid deformation method. As the surfactant has a non-uniform distribution during the drop formation in general, the surface tension has a gradient on the interface, which affects the flow field and interface evolution. The surfactant effect is discussed for dripping and jetting regimes.
© EDP Sciences, Springer-Verlag, 2013