Effect of Relative Energy Difference (RED) of Coagulation Bath on the Structure of Polysulfone Membrane

Phase inversion is one of the favorite methods for preparation of polysulfone (Psf) membranes. Some main factors such as: solvent and non-solvent exchange rate, phase inversion process, thereby, they can influence membrane structure. This study focused on the relative energy difference (RED) of coagulation bath which extracted from Hansen solubility parameters. Ethanol and water were selected as coagulant and effect of RED in different composition of ethanol/water was investigated. Results showed that at high concentrations of ethanol in coagulation bath, morphology of membranes declined to a sponge like structure and size of macrovoids was decreased due to the reducing of RED. On the other hand, precipitation time and porosity of membranes were increase accordingly.