Study on the interfacial micro-voids of poly(vinylidene difluoride)/polyurethane blend membrane

The poly(vinylidene difluoride)/polyurethane (PVDF/PU) blend membrane was prepared using the method of immersion-precipitation process. The influence of the miscibility of the two polymers on the formation of the interfacial micro-voids (IFMs) of the blend membranes was analyzed by the theory of thermodynamics and discussed with DMA, DSC and SEM. The effect of working pressure on the pure water flux (PWF) of the IFMs was also studied using membrane instrument. Results show that the IFMs are formed due to the miscibility of PVDF and PU. The existence of IFMs attributes much to the PWF of the PVDF/PU blend membrane, and the PWF of the IFMs is related not only to the miscibility of PVDF and PU but also to the deformation of IFMs under working pressure.