Pore size distributions in microporous membranes .2. Bulk characterization of track-etched filters by air porometry and mercury porosimetry

The structure and morphology of several Cyclopore filters, consisting of thin track-etched sheets of polycarbonate, is analyzed here through an extended bubble point method and mercury intrusion porometry. Relevant morphological parameters have been studied for six types of filters (C01, C02, C04, C06, C08, and C10). The bulk pore size distributions are directly obtained for each filter. The statistical distributions are studied thoroughly and those obtained from both methods are compared. Specific surface areas are also obtained from both methods and compared with those directly measured in BET experiments with fair agreement. Scanning electron microscopy (SEM) and computerized image analysis (CIA) were previously used to characterize and analyze the surface pore size distributions. They are also compared with those obtained here, confirming the previous assumption of inner widenings in the pores. (C) 1995 Academic Press, Inc.