Fluid Front Dynamics Characterization in Confined Microchannels and Porous Media. Pumps, Lubricants, Defects, Hydrogels and Organ-on-a-chip
[eng] This thesis presents the results of three and a half years of research on fluid front dynamics, porous media and microfluidics through five interconnected studies. While these fields provide the general framework, this work explores specific topics, including liquid pumping, capillary-driven f...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/225927 |
| Acceso en línea: | https://hdl.handle.net/2445/225927 http://hdl.handle.net/10803/696387 |
| Access Level: | acceso abierto |
| Palabra clave: | Dinàmica de fluids Microfluídica Capilaritat Materials porosos Fluid dynamics Microfluidics Capillarity Porous materials |
| Sumario: | [eng] This thesis presents the results of three and a half years of research on fluid front dynamics, porous media and microfluidics through five interconnected studies. While these fields provide the general framework, this work explores specific topics, including liquid pumping, capillary-driven flow, materials characterization, and microfluidic design for biomedical applications. This research establishes a theoretical framework based on fluid dynamics principles, supported by experimental characterization and advanced fabrication processes to validate the hypotheses. A central theme of this research is the interplay between fluid flow dynamics and complex materials, with a focus on controlling and optimizing flow behaviors in confined environments. Using theoretical modeling, experimental validation, and material engineering, this work advances our understanding of key processes that govern liquid transport in natural and engineered systems. The research is divided into five different parts, among two parts of the Introduction and Conclusions. The first three parts, not counting the introduction, are related to each other under the title Fluid Front Dynamics: Pumps, Lubricants and Defects. In the first case, we investigate air-permeable porous media pumps, developing a mathematical model to describe their performance. These pumps operate without external power sources, offering an innovative solution for microfluidic transport. The interplay between air diffusion and liquid displacement plays a crucial role in their efficiency. In the second case, we study imbibition in SLIPS-coated channels, optimizing spontaneous capillary flow. By reducing friction with lubricant-infused sur-faces, we demonstrate a mechanism to accelerate capillary-driven transport, a fundamental challenge in passive microfluidic systems. The third, analyzes front flow in single-defect channels, examining how surface roughness influences pinning effects. Pinning-induced variations in capillary pressure provide insights into how microscale irregularities impact fluid motion, a key consideration in both lab-on-a-chip technologies and industrial microfluidic systems. Next, the two remaining parts are also related under the title, Bio-Mimetics: Hydrogels and Organ-on-a-Chip. In the fourth, then, we focus on measuring and tailoring the hydrogel properties and improving their structure to enhance key characteristics. Hydrogels, as a class of soft porous materials, provide tunable properties that influence their permeability and mechanical behavior, making them highly relevant for biomedical and filtration applications. Finally, we design a spleen-on-a-chip system for malaria testing, mimicking the spleen’s function to detect diseases in cells. This bioinspired microfluidic device integrates porous media and microchannel networks to recreate physiologically relevant conditions for blood filtration and parasite detection. Each of these studies contributes to a deeper under-standing of fluid behavior in microfluidic and porous systems, with implications for both fundamental science and applied engineering. Together, these findings improve our ability to design efficient and power-free fluid transport systems, improve material properties for biomedical applications, and refine theoretical models that describe the front between liquid and air behavior in confined geometries. The synergy between the behavior of porous media, capillary-driven dynamics, and engineered microfluidic designs underscores the importance of interdisciplinary approaches in tackling complex fluidic challenges. |
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