Fluid viscoelasticity suppresses chaotic convection and mixing due to electrokinetic instability

When two fluids of different electrical conductivities are transported side by in a microfluidic device under the influence an electric field, electrokinetic instability (EKI) is often generated after some critical values applied field strength and conductivity ratio. Many prior experimental numerical studies show that this phenomenon results chaotic flow inside microdevice, thereby facilitating mixing if they Newtonian behavior. However, present study shows convection arising due to can be suppressed viscoelastic instead ones. In particular, we observe as Weissenberg number (ratio elastic viscous forces) gradually increases polymer viscosity ratio solvent zero-shear rate polymeric solution) decreases, fluctuation T junction decreases within range conditions encompassed study. We demonstrate suppression motion occurs formation strand high stresses at interface fluids. further (particularly, span-wise one) inhibits Therefore, one needs cautious when EKI planned use for such Our observations line with seen limited conducted these kinds