Rapid microfluidic mixers utilizing dispersion effect and interactively time-pulsed injection

Jik Chang Leong, Chien Hsiung Tsai, Chin Lung Chang, Chiu Feng Lin, Lung Ming Fu

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


In this paper, we present a novel active microfluidic mixer utilizing a dispersion effect in an expansion chamber and applying interactively time-pulsed driving voltages to the respective inlet fluid flows to induce electroosmotic flow velocity variations for developing a rapid mixing effect in a microchannel. Without using any additional equipment to induce flow perturbations, only a single high-voltage power source is required for simultaneously driving and mixing sample fluids, which results in a simple and low-cost system for mixing. The effects of the applied main electrical field, interactive frequency, and expansion ratio on the mixing performance are thoroughly examined experimentally and numerically. The mixing ratio can be as high as 95% within a mixing length of 300 μm downstream from the secondary T-form when a driving electric field strength of 250 V/cm, a periodic switching frequency of 5 Hz, and the expansion ratio M= 1 : 10 are applied. In addition, the optimization of the driving electric field, switching frequency, expansion ratio, expansion entry length, and expansion chamber length for achieving a maximum mixing ratio is also discussed in this study. The novel method proposed in this study can be used for solving the mixing problem in the field of micro-total-analysis systems in a simple manner.

Original languageEnglish
Pages (from-to)5345-5352
Number of pages8
JournalJapanese Journal of Applied Physics
Issue number8 A
Publication statusPublished - 2007 Aug 6

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)


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