Effect of polymer concentration and temperature of delay stage on the structure of PES membranes

In this research, polyethersulfone membranes were prepared by phase inversion method including a delay stage at different temperatures before immersing the casted polymeric films in a coagulation bath containing non-solvent; and membrane samples were casted from solutions with different concentrations of polyethersulfone as the membrane-forming polymer in dimethylacetamide as the solvent. In order to coagulate the polymer solutions, distilled water was used as the non-solvent of polyethersulfone. The effect of polymer concentration and temperature at the delay stage on the membrane structure, were investigated by scanning electron microscopy photographs. The results obtained illustrate that, with increasing the polymer concentration in samples prepared without delay stage, more sponge-like areas are formed in the cross sectional structure of the membranes. Also, by applying delay stage, the cross sectional structure is compacted. By increasing the temperature in the delay stage, solvent has been evaporated from the casted solution, so non-porous and transparent thin films gets formed after immersing the casted film in the coagulation bath.

Keywords:

Membrane , Polyethersulfone , Concentration , Temperature , Structure