Water vapor permeation and morphology of polysulfone membranes prepared by phase inversion

Abstract

The aim of this work was to study the effect of different variables in the morphology and water vapor permeation of asymmetric membranes. Different from other works on vapor induced phase inversion this work focus on the formation of a dense skin capable of separating small molecules like gases and on the transport properties of water vapor instead of liquid water. It also correlates the morphologies with the permeability. The results show that higher polymer concentrations lead to denser skin and lower permeability. Water vapor transmission rates varied from 30 to 48 g/m².h depending on membrane morphology. They also show that for membranes with the same type of skin layer the permeability depends on the sub-layer. Finally, the results suggest that different mechanisms were responsible for the formation of the membranes.

Keywords:
asymmetric membranes; vapor induced phase inversion; water vapor permeation