Nanoporosity of polymer membranes and corresponding powder materials on the bases of gas sorption results and positron annihilation experiments

Variations of nanoporosity obtained on casting of membranes from the original highly dispersed polyphenylene oxides (PPO) of various crystallinity (from 0 to 69.2%) on the bases of the data, obtained by the methods of positron annihilation and low temperature gas (N2, CO₂) sorption, are discussed. The notion of nanoporosity includes microporosity and mesoporosity of the materials with pore sizes from some Å up to several tens of nanometers. A combination of the results of positron annihilation and sorption measurements with oxygen permeation data for the created membranes allow to conclude that, on transition from powder to solid membrane, microporosity is mostly stays unhanged while mesoporosity essentially transforms.