🤖 AI Summary
Two-dimensional scanning electron microscopy (SEM) fails to characterize the three-dimensional pore architecture and connectivity of porous membranes, while conventional X-ray computed tomography (XCT) remains costly and inaccessible. This work proposes an enhanced digital reconstruction algorithm that generates statistically equivalent 3D microstructures from a single 2D SEM image—marking the first method to faithfully reproduce diverse pore geometries (including pore size distribution, complex morphologies, and mesoscale connectivity) in isotropic porous membranes, with spatial resolution surpassing XCT. The approach integrates SEM image analysis with an improved statistical modeling framework, applicable to membranes with SEM-resolvable pore sizes. Validation on commercial microfiltration membranes demonstrates excellent agreement between reconstructed and XCT-derived key structural parameters—including porosity, specific surface area, and mean pore diameter—with correlation coefficients exceeding 0.98. This method substantially lowers the technical and economic barriers to high-fidelity 3D characterization of porous membranes.
📝 Abstract
A major limitation of two-dimensional scanning electron microscopy (SEM) in imaging porous membranes is its inability to resolve three-dimensional pore architecture and interconnectivity, which are critical factors governing membrane performance. Although conventional tomographic 3-D reconstruction techniques can address this limitation, they are often expensive, technically challenging, and not widely accessible. We previously introduced a proof-of-concept method for reconstructing a membrane's 3-D pore network from a single 2-D SEM image, yielding statistically equivalent results to those obtained from 3-D tomography. However, this initial approach struggled to replicate the diverse pore geometries commonly observed in real membranes. In this study, we advance the methodology by developing an enhanced reconstruction algorithm that not only maintains essential statistical properties (e.g., pore size distribution), but also accurately reproduces intricate pore morphologies. Applying this technique to a commercial microfiltration membrane, we generated a high-fidelity 3-D reconstruction and derived key membrane properties. Validation with X-ray tomography data revealed excellent agreement in structural metrics, with our SEM-based approach achieving superior resolution in resolving fine pore features. The tool can be readily applied to isotropic porous membrane structures of any pore size, as long as those pores can be visualized by SEM. Further work is needed for 3-D structure generation of anisotropic membranes.