Relationship between Energy Characteristics of Surface of Polymeric Membranes and Their Transport Properties

Abstract

Molecular theory of wetting was used to calculate the specific free surface energy of membranes based on amorphous polymers of varied chemical structure from experimental wetting angles obtained for test fluids. A relationship was found between the dispersion component of the surface energy of a membrane, its gas permeability, and free volume of the polymer. This makes it possible to employ the wetting method to prognosticate the transport properties of polymeric membranes. In wetting of membranes with aqueous solutions of alcohols, the concentration of an alcohol corresponding to the onset of its sorption into the membrane was determined. The correlation of the value obtained with the alcohol concentration that corresponds to the onset of sorption and is determined independently by the gravimetric method enables use of wetting angles for optimizing the conditions of experiments on nanofiltration and pervaporation.