Mohammad. Khosravi - Department of Chemical Engineering, Engineering Faculty, University of Tehran, Tehran, Iran
Zahra. Mansourpoor - Department of Chemical Engineering, Engineering Faculty, University of Tehran, Tehran, Iran
Azadeh. Ghaee - Department of life sciences Engineering, Faculty of new science and Technologhies, University of Tehran, Tehran, Iran
Ali. Ghadimi - Novel Technology Research Group, Petrochemical Research and Technology Company, National Petrochemical Company, Tehran, Iran

Porous asymmetric hydrophobic membranes were prepared from poly (vinylidenefluoride) (PVDF) polymeric materials by the phase inversion process induced by a nonsolvent. The effect of pore-forming hydrophilic additives on the membrane morphology was investigated. With a focus on the PVDF/DMAc system, the effects of various additives such as Methanol, Glycerol, Lithium chloride (LiCl), Polyethylene glycol (PEG400) and Acetic acid on the resulting membrane morphology were investigated. The thermodynamic precipitation rate of the polymer solution with the different additives was studied using cloud point measurement. The membrane morphology was examined with scanning electron microscopy (SEM). The cross-sectional structure of the membranes showed for different non solvent addtive longer finger-like structure was formed due to rapid liquid–liquid demixing which can be attributed to the strong diffusion power between coagulation bath medium (water) and solvent–nonsolvent additives

polymer,poly (vinylidene fluoride) (PVDF), the membrane, additives, morphology