Different types of bore fluids were tested and dimethyl sulfoxide (DMSO) was selected as the optimal bore fluid to eliminate the inner skin.Various concentrations of DMSO in the outside coagulation bath (0～60%) and different coagulation temperature (20～80℃) were used for investigation.The structure of the hollow fiber was examined using scanning electron microscopy (SEM).Thickness of the outer skin decreased with increasing the coagulation temperature.As a result

the membrane flux was enhanced by 2 times as the temperature was increased

while the retention for bovine serum albumin (BSA) and pore size of the membrane did not change significantly.