In this study, the concentration of solvent in the coagulation bath as a function of time for polymeric solutions was studied. Poly vinylidene fluoride (PVDF) as polymer, Dimethylacetamide (DMAc) as solvent, PEG and LiCl as additives, were used. The concentration of solvent in the coagulation bath is related to the non-solvent and solvent exchange rate. The result showed that time lag in the non-solvent and solvent exchange is due to the distance of sampling location from the cast film and also, the high viscosity of the solution due to additives, which leads to increasing in the mass transfer resistance of phase separation.
