An approach for quantitative analysis of pore size distribution of silica gel using atomic force microscopy

This article discusses a direct approach for assessing irregularly shaped pore distribution of porous materials using Atomic Force Microscopy (AFM). Using the tapping mode, AFM is employed to obtain the surface topographic information of the porous materials commonly used in adsorption applications. Three different types of silica gels, commercially used silica–alumina and acetaminophen samples are investigated using an image processing technique to capture the pore size-related information. Macro and mesopores in a specified region are visualized then quantified and counted using 2-D Fast Fourier Transformation (2D FFT) technique. The results obtained by the AFM technique are then compared with the BET surface area and pore size distribution (NLDFT) extracted from the N₂ adsorption isotherms.