Chaotic vortex micromixer utilizing gas pressure driving force

A novel chaotic vortex micromixer is proposed comprising an open mixing chamber, a sealed mixing chamber and a serpentine microchannel. In the proposed approach, the samples are loaded into the open chamber and an external gas pressure driving force is then applied. The driving force generates a chaotic vortex structure in the open chamber and drives the samples through the serpentine channel into the sealed chamber. As the samples fill the sealed chamber, a compression reaction force is produced, which generates a second chaotic vortex structure and drives the samples back to the open chamber. The vortex structures perturb the sample streams and therefore prompt an efficient mixing of the two species. The flow phenomena within the mixing chambers are evaluated by means of numerical simulations. The numerical results are verified by performing flow visualization experiments. A good agreement is found between the two sets of results. It is shown that a reaction ratio of almost 100% is obtained within 6 s given a gas pressure driving force of 1.5 kg/cm2. Overall, the results show that the micromixer proposed in this study provides a simple solution for mixing problems in Lab-on-Chip systems.

► A PMMA-based chaotic vortex passive micromixer is proposed.
► An external gas pressure driving force is applied to the samples contained within the open chamber.
► The driving force prompts the formation of a chaotic vortex structure.
► A gas pressure driving force of 1.2 kg/cm2 is sufficient to drive the sample fluids.
► A reaction ratio of 99.9% is achieved within 6 s.