Determination of pore radius distribution of porous polymeric membranes by electron microscopic method

Abstract

An attempt was made to establish a method for evaluating the pore characteristics of porous polymeric membrane having the mean pore diameter larger than 10 nm through electron micrograph with help of stereology (EM method). For this purpose, ellipsoidal, spherical, and straight-through cylindrical pore models were adopted. Theoretical equations relating the pore radius distribution function N(r) to the distribution function F(x) of the length x of test lines cut off by pores in an electron micrograph were derived as follows;where, Φe is a shape factor and the suffix e and s denote ellipsoidal and spherical pores. The mean pore radii, porosity, and pore radius distribution functions were evaluated from N(r) and compared with those determined by various methods including mercury intrusion, fluid permeability and bubble pressure, flow rate, surface area, apparent density, and swelling methods for porous regenerated cellulose membrane prepared by micro-phase separation method and polycarbonate membrane Nuclepore®. © 1985 The Society of Polymer Science, Japan.