A predictive model for tuning additives for the fabrication of porous polymeric membranes

In order to study the influence of the preparation conditions on the performance of the polyvinylidene fluoride (PVDF) flat membranes, which were prepared via phase inversion method, a set of experiments based on response surface methodology (RSM) of central composite design (CCD) for three variables with five levels was performed. N,N-dimethyleacetamide (DMAc) and polyvinylpyrrolidone (PVP) were employed as solvent and pore former additive, respectively. PVDF and PVP conditions in the casting solution as well as the ethanol content in the coagulation bath were set as main manufacturing variables. Interactions of the preparation variables besides their quadratic main effects and on the desired responses namely; pure water flux, mean pore size, tensile strength, morphology and the porosity of the prepared membranes were investigated. The predicted and experimental results were found to be in good agreement (R2 values of 0.97, 0.95, 0.91 and 0.81 for pure water flux, mean pore size, tensile strength and porosity respectively, were obtained). The applicability of the CCD based RSM for the performance modeling of PVDF flat sheet membranes has been successfully evaluated.