Assessment of three AC electroosmotic flow protocols for mixing in microfluidic channel

Jia Kun Chen, Chi Neng Weng, Ruey Jen Yang

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


This study performs an experimental investigation into the micromixer capabilities of three different protocols of AC electroosmotic flow (AC EOF), namely capacitive charging (CC), Faradaic charging (FC) and asymmetric polarization (AP). The results reveal that the vortices generated by the FC protocol (the frequency is around 50-350 Hz) are stronger than those induced by the CC protocol (the frequency is higher than 350 Hz), and therefore provide an improved mixing effect. However, in the FC protocol, the frequency of the external AC voltage must be carefully controlled to avoid damaging electrodes as a result of Faradaic reactions. The experimental results indicate that the AP polarization effect (the applied voltage and frequency are V1 = 1 Vpp and V2 = 20 Vpp/5 kHz) induces more powerful vortices than either the CC protocol or the FC protocol, and therefore yields a better mixing performance. Two AP-based micromixers are fabricated with symmetric and asymmetric electrode configurations, respectively. The mixing indices achieved by the two devices after an elapsed time of 60 seconds are found to be 56.49 % and 71.77 %, respectively. This result shows that of the two devices, an asymmetric electrode configuration represents a more suitable choice for micromixer in microfluidic devices.

Original languageEnglish
Pages (from-to)1267-1273
Number of pages7
JournalLab on a Chip
Issue number9
Publication statusPublished - 2009

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Biochemistry
  • Chemistry(all)
  • Biomedical Engineering

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