Effect of support on PVDF membranes for distillation process

Flat sheet membranes made of polyvinyldene fluoride (PVDF) were prepared via nonsolvent induced phase separation (NIPS). The focus of this work was concentrated on the effect of the support structure and material on the morphology and on the distillation performance of the final membranes. To this end, various membranes were prepared casting a uniform polymer solution film on six commercial non-woven tissues and on three thin nets, characterized by different materials and morphologies, and then immersing them in an ethanol coagulation bath. FE-SEM analysis was widely exploited to evaluate both the surface and cross section structure of membranes. The different interactions between the dope solution and the support materials as well as the different extent of mutual entanglement were found to be key parameters in the membrane preparation, governing both the overall porosity and pore size.