Precise manufacturing and performance validation of paper-based passive microfluidic micromixers

Abstract

Micromixers are one of the most frequently used components in microfluidics. Passive micromixers are an emerging type with unique features in terms of reliability, robustness and efficiency. Hence, this study aimed to design, fabricate and test new multilayered passive micromixers consisting of three ad hoc layers, by means of a precise and cost-effective xurography manufacturing technique. The first and third layers are PVC foils, whereas the second layer is paper, incorporating microchannels of straight line or zig-zag configuration. Three different types of papers were analyzed as materials for the middle layer. Results demonstrated that immersing the papers into paraffin wax resulted in significantly improved physical characteristics, including solidification and intactness that reduced leakage of fluids into inside channels, thereby enhancing internal efficacy and delivery mechanisms. Subsequent assessments were carried out on mixing performance at various flow rates, pattern-related flow rates at various pressures and paper types, and results showed the impact of a zig-zag vs. straight line configuration, demonstrating the importance of flow patterns on features of micromixers and their applications in microfluidic devices. Furthermore, image analysis was conducted to determine mixing efficiency of the proposed microfluidic micromixers.