A NEW COMPUTATIONAL TECHNIQUE FOR THE ANALYSIS OF DIFFUSION PERMOPOROMETRIC DATA FOR ASYMMETRIC MEMBRANES

A modified technique for the analysis of diffusion permoporometric dat a obtained with asymmetric membranes has been described. The modificat ions allow better estimates of pore sizes and pore size distributions to be made. The erroneous nature of the conclusions that would be draw n if permoporometric data, obtained with a membrane with asymmetric po res, is treated under the assumption of right cylindricity has been de monstrated by means of such an analysis done on a hypothetical asymmet ric membrane. While there is little error in the estimation of pore ra dii, the pore numbers are grossly overpredicted by the cylindrical por e model. The extent of this overprediction is directly proportional to the asymmetry of the membrane and the thickness of its active layer.