Microfluidic Model Porous Media: Fabrication and Applications

Abstract

Complex fluid flow in porous media is ubiquitous in many natural and industrial processes. Direct visualization of the fluid structure and flow dynamics is critical for understanding and eventually manipulating these processes. However, the opacity of realistic porous media makes such visualization very challenging. Micromodels, microfluidic model porous media systems, have been developed to address this challenge. They provide a transparent interconnected porous network that enables the optical visualization of the complex fluid flow occurring inside at the pore scale. In this Review, the materials and fabrication methods to make micromodels, the main research activities that are conducted with micromodels and their applications in petroleum, geologic, and environmental engineering, as well as in the food and wood industries, are discussed. The potential applications of micromodels in other areas are also discussed and the key issues that should be addressed in the near future are proposed.

Pore‐Scale Flow Characterization of Polymer Solutions in Microfluidic Porous Media

“…Microfluidics provides the ability to design pore space geometries at length scales relevant to real‐world porous media, with spatial resolutions as small as ≈50 nm. Furthermore, photolithography allows for fabrication of a wide range of complex microfluidic designs that can recapitulate pore space geometries, and can be used to systematically test the influence of different geometric parameters on flow behavior . Finally, microfluidic devices can be designed to be optically transparent, enabling pore‐scale flow visualization using optical imaging.…”

“…Furthermore, photolithography allows for fabrication of a wide range of complex microfluidic designs that can recapitulate pore space geometries, and can be used to systematically test the influence of different geometric parameters on flow behavior. [44] Finally, microfluidic devices can be designed to be optically transparent, enabling pore-scale flow visualization using optical imaging. Such platforms thus enable systematic characterization of the flow patterns, polymer elongation dynamics, and flow fluctuations during polymer solution flow through model porous media.…”

Omniphobic ZIF‐8@Hydrogel Membrane by Microfluidic‐Emulsion‐Templating Method for Wound Healing

“…In addition to their bactericidal and anti‐inflammatory properties, the slowly released copper and zinc ions have shown to accelerate wound healing by promoting cell migration, angiogenesis, and collagen deposition 25,28,29,32,33. Benefiting from a microfluidic‐emulsion‐templated method, we successfully encapsulate a model example of MOFs, zeolitic imidazolate framework‐8 (ZIF‐8), in a well‐defined porous polyvinyl alcohol (PVA) hydrogel membrane with exquisite reentrant microstructures 20,21,34,35. The resultant MOFs@PVA composite hydrogel membrane exhibits a large apparent CA of 120° for physiological fluids.…”

Enhanced oil recovery mechanism and recovery performance of micro‐gel particle suspensions by microfluidic experiments

“…Even though the flow in a 2D microchip is not exactly the same as that in 3D rocks, some appropriate features of real rocks can still be represented by microfluidic systems fabricated with different geometries . More importantly, visualized microfluidics experimental results can be compared with numerical simulation results directly, which could make up disadvantages of microfluidics in 3D geometry.…”