Various methods have been used to characterize ultrafiltration membranes, such as gas flux measurements, (field emission) scanning electron microscopy, permporometry and liquid-liquid displacement. Significant differences in the pore size distributions determined from permporometry and liquid-liquid displacement were found.
Germic, J., Germic, J., Ebert, K., Ebert, K., Bouma, R. H. B., Bouma, R. H. B., ... Strathmann, H. (1997). Characterization of polyacrylonitrile ultrafiltration membranes. Journal of membrane science, 1997(132), 131-146. https://doi.org/10.1016/S0376-7388(97)00058-6