Microfluidic mixing on application of traveling wave electroosmosis

Abstract

Microanalysis systems benefit from various advantages, such as their portable size, low cost, high accuracy, and short measurement times, prompting the development of numerous “lab-on-a-chip” techniques in recent decades. Biochemical applications of these techniques often require the rapid mixing of different fluid samples. This study presents a novel mixing technique using a four-phase traveling-wave electrode array. Traveling-wave electrode arrays subjected to alternating current (AC) signals are arranged on both sides of the microchannel walls, creating an overall chaotic mixing mechanism for a short microchannel and a low amplitude applied AC voltage. Numerical analyses reveal that the symmetric/asymmetric circulation zone can be generated by switching the phase-shift arrangement of the electrodes. The symmetric/asymmetric circulation zone involves convective and diffusive mixing mechanisms. The electrolyte conductivity, frequency, channel width and depth, and average inlet velocity affect the mixing performance. When the traveling-wave electrode arrays are implemented with 3D structures, the mixing efficiency is enhanced with a maximum achievable mixing quality of 98%.