Assessment of three AC electroosmotic flow protocols for mixing in microfluidic channel.
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 V(1) = 1 V(pp) and V(2) = 20 V(pp)/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.
Chen
Jia-Kun
JK
Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan.
Weng
Chi-Neng
CN
Yang
Ruey-Jen
RJ
D045424:Complex Mixtures / Q000737:chemistry* / Q000302:isolation & purification* / Q000528:radiation effects; D003198:Computer Simulation; D017076:Computer-Aided Design; D004574:Electromagnetic Fields; D004586:Electrophoresis / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008956:Models, Chemical; D009997:Osmotic Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D045424:Complex Mixtures