Influence of quench medium on the structures and gas permeation properties of polysulfone membranes made by wet and dry/wet phase inversion

Essentially defect-free integrally-skinned asymmetric polysulfone membranes were fabricated by a dry/wet phase inversion process using forced-convective evaporation. The choice of the quench medium is of utmost importance for the formation of gas separation membranes having high selectivities combined with high gas fluxes. The integrally-skinned asymmetric membranes were characterized by gas permeation measurements and field emission scanning electron microscopy. This study indicates that the phase separation and vitrification processes occurring during the wet phase inversion step should be as rapid as possible to generate the highest performance gas separation membranes.