Effect of non-solvent concentration in the coagulation bath on water permeability of PES membrane

A semipermeable membrane made of Polyethersulfone (PES) has been optimized. This research was conducted to have the optimum composition of coagulation bath in fabricating high water permeability membrane. PES with a molecular weight of 45000 Da was used as the basic material together with Polyethyleneglycol (PEG) and N- Dimethylacetamide (DMAc) as the additive and the solvent, respectively. Coagulation bath was done in gelatinization media composed of pure water by varying concentration of N-Methyl-2-Pyrrolidone (NMP) to 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.%, and 7 wt.%. Diffusion test showed that the addition of NMP at a concentration of 7 wt.% has increased the water permeability and diffusion coefficient of NaCl molecule by 78.6%. To conclude, adding NMP into coagulation bath improve water permeability and surface membrane hidrophilicity of PES membrane.