Exploring Capillary Flow in Paper-Based Microfluidics: Unraveling Mechanics and Applications

Abstract The present paper is a comprehensive exploration of the intricate mechanics and applications of capillary-driven flow, specifically delving into the wicking phenomenon within the realm of paper-based microfluidics. The study employs extensive numerical simulations to unravel the dynamics of liquid wicking within a paper strip, with a keen focus on key parameters such as porosity, permeability, capillary radius, surface tension, and viscosity. The accuracy of the simulation model is rigorously validated against the Lucas-Washburn equation, thereby establishing a robust foundation for insights crucial to the optimization of microfluidic devices. The research emphasizes the paramount importance of parameter control in achieving specific capillary rise behaviors. Significant observations include the augmentation of capillary rise with higher surface tension, evident in the pronounced meniscus, and the facilitating role of larger, well-connected pores and higher porosity in promoting increased capillary rise. Furthermore, the study explores the interplay between viscosity and cohesive forces, revealing that higher viscosity strengthens cohesive forces while diminishing surface tension, thus influencing capillary rise. These findings collectively advance the understanding of paper-based microfluidics, offering a robust foundation for practical applications in diverse domains. From healthcare diagnostics to environmental monitoring and quality assessment in the food industry, the research contributes valuable knowledge to the evolving field of microfluidic technology.