Preparation of polyvinylidene fluoride membrane via dual coagulation bath system and its wettability study

Hydrophobic polyvinylidene fluoride (PVDF) membrane has been successfully developed using dual coagulation bath system in which first coagulation bath produced membrane with nodular structure whereas second water coagulation bath provided membrane with porous structure. The effects of coagulation time, polymer concentration, and isopropanol/water ratio in first coagulation bath on membrane wettability were studied. The membrane surface morphology such as pore size and porosity were studied using field emission scanning electron microscope and porosimeter. The wettability of the membrane was determined using sessile drop contact angle measurement. Using dual‐coagulation bath system, it was found that membrane with bicontinuous structure tends to have higher water contact angles. This membrane could be produced through short immersion time of 18 wt % PVDF solution in soft nonsolvent bath followed by coagulation in water nonsolvent bath. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012