Poly (Vinylidene Fluride) Membrane Preparation and Characterization: Effects of Mixed Solvents and PEG Molecular Weight

In this study, polyvinylidene fluoride (PVDF) ultrafiltration membranes were prepared via immersion precipitation method using a mixture of two solvents triethyl phosphate (TEP) and dimethylacetamide (DMAc), which had different affinities with the nonsolvent (water). Properties of the prepared membranes were characterized using scanning electron microscope (SEM) and contact angle and membrane porosity measurements. The prepared membranes were further investigated in terms of pure water flux and BSA rejection in cross flow filtration experiments. The results showed that by using a mixture of DMAc and TEP as solvent and changing the mixed solvent composition, membranes with different morphologies from sponge-like to macrovoid containing were obtained.
Maximum flux of the prepared membranes with different solvent mixing ratios was obtained for the one with 60%wt TEP in the casting solution of PVDF/TEP-DMAc/ PEG which equals to 76.8 lm-2h-1. The effect of addition of polyethylene glycol with different molecular weight on morphology and performance of the membranes has also been discussed.