Development of a pore construction data analysis technique for investigating pore size distribution of ultrafiltration membranes by atomic force microscopy

Abstract

A new data analysis method, the pore construction technique, was developed for use in analyzing images resulting from atomic force microscopy (AFM). This technique was developed to overcome the limitations of traditionally employed methods for determining the pore size distribution and characterization of membranes. The method was developed using Matlab software. It starts by detecting all regions in the image that have a 3D conical pore geometry. The pore data is then extracted, and data filters are applied to determine the final shape and dimension of each pore in the image. The pore construction technique was applied to AFM images obtained from a commercial ultrafiltration membrane, and resulted in consistent pore size distribution data from three different membrane fibers. The new technique also provided additional membrane characteristics including porosity and pore density, and could automatically detect membrane pores, all of which cannot be done by AFM manual cross-section methods. The pore construction technique resulted in membrane pore size distribution profiles that were similar to FE-SEM results. These improvements in AFM image analysis resulted in reliable and essential pore size data which will make AFM a more valuable tool for membrane characterization and similar applications.