Affecting parameters on the microstructural morphology of polysulfone membranes via nonsolvent induced phase separation

Flat sheet polysulfone membranes were prepared by phase inversion process. The effect of composition and temperature of coagulation bath and concentration of polymer in dope solution on the morphology of membranes were investigated. Changing the bath composition from pure water to the solution with composition of 60/40 (w/w) of NMP and water increased the porosity of top layer and the finger-like macrovoid structure near the support side of the membranes was decreased. The same result observed when coagulation bath temperature increased from 25 °C to 60 °C The morphology of membranes was analyzed by scanning electron microscope and performance of membranes was investigated in terms of pure water permeability and tensile strength. The experimental results show that increasing polymer concentration from 12 to 15 wt%, decreases pure water permeability and increases tensile strength. For both polymeric compositions, with increasing of coagulation bath temperature, the tensile strength and pure water permeability of the membranes increased, simultaneously.