pH-responsive poly(vinylidene fluoride)/poly(acrylic acid) porous membranes prepared via an vapor induced phase separation technique for removing copper ions from water

Here, polyvinylidene fluoride/poly (acrylic acid) (PVDF/PAA) membranes were fabricated via vapor-induced phase separation (VIPS) process for the first time. The casting solution was synthesized via in situ cross-linking polymerization of AA in PVDF solution and spread into glass plate. After holding in water vapor for a determined exposure time, they were soaked in the water bath. With the increase of exposure time, the membrane surface changed from dense morphology to petal-like structure, and the concentration of carboxyl groups on the membrane increased. The fabricated membranes exhibited strong pH-dependent permeability and high adsorbing capacity of Cu2+ ions from water.