Development of PDMS-glass hybrid microchannel mixer composed of micropillars and micronozzles

Abstract

In this research, a microchannel type mixer composed of micropillars and micronozzles was developed for effective mixing of biochemical samples. To estimate the performance of the new designed micromixer, flow patterns were simulated using the computational fluid dynamics software. The simulation showed that the mixing efficiency increased from 87.9% to 97.5% as the flow rate varied from 50 to 500 Pl/min. When liquid were injected into the fabricated micromixer, it was difficult to prime the microchannel because of hydrophobicity of PDMS surface. To overcome this problem, the inside of the micromixer was coated with PVP (polyvinylpyrrolidone). It was found that over 0.25 wt.% PVP concentration in the DI water solution was recommendable. After appropriate PVP coating, the DI water and the mixture of blue dye and DI water were mixed in the fabricated micromixer and the mixing efficiency was measured. The mixing efficiency increased from 68.8% to 92.6% as the flow rate increased from 50 to 500 Pl/min. The new micromixer showed very good mixing performance when the flow rate was over 300 Pl/min. Due to the simple structure and uncomplicated fabrication process, the proposed micromixer can be easily integrated to the micro total analysis system (µ-TAS) or lab-on-a-chip.