Determining Porosity and Permeability from AFM Images Using Image to Curve in COMSOL Multiphysics

D. Zhurauliova1, J. Smilek1, M. Pekař1
1Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic
发布日期 2024

In recent years, Atomic Force Microscopy (AFM) has played a key role in the characterisation of surface structures and materials at the microscopic level. One of the most important aspects of AFM image analysis is the reliable provision of pore size and cross-linking rate data. AFM uses a sharp tip that bends under applied forces, allowing the beam to scan the surface and capture any irregularities. This data can be used to create a magnified image of the sample, which is particularly important for biopolymers and hydrogels used in tissue engineering and other biotechnological applications [1]. In this work, we focused on the calculation of porosity and permeability based on the 2D geometry obtained from an AFM image showing the surface of a 2% agarose-based hydrogel. This calculation was performed using the Image to Curve module and the Creeping Flow interface of the COMSOL Multiphysics software. The Image to Curve module allows an image to be used as a starting point for analysis by generating an interpolation curve from the contour of the imported image, which can then be used as part of the geometry. This conversion creates extraneous areas that must be removed to obtain an accurate geometry profile and ensure the accuracy of the calculation [2]. The Navier-Stokes equations are fundamental equations describing the motion of fluids, considering the viscous and compressive forces acting on the fluid. In cases where the Reynolds numbers are very small, which is typical at microscale and low velocities, the inertial forces become negligible compared to the viscous forces. This simplified Stokes flow model allows for more efficient calculations and analyses. The Creeping Flow interface in COMSOL Multiphysics software is specifically designed to simulate fluid flow at very low Reynolds numbers. Using this interface simplifies calculations, enables accurate simulations, and allows the extraction of key material properties such as porosity and permeability, which are essential parameters for various applications in materials engineering and biomedical sciences [3]. Using the Image to Curve module and the Creeping Flow interface, we can quantitatively evaluate porosity and permeability based on their morphology and structure. This allows you to design and optimise materials for specific needs, or continue your work using the full range of modelling and simulation capabilities available in COMSOL Multiphysics software.