Trade-off between thermodynamic enhancement and kinetic hindrance during phase inversion in the preparation of polysulfone membranes

摘要: Polysulfone membranes were prepared via the diffusion-induced phase inversion process from casting solutions consisting of polysulfone, dimethyformamide, and polyvinyl pyrrolidone as a polymeric additive. The effect PVP added in was analyzed by measuring membranes' morphology water permeability. Variations solution's thermodynamic kinetic properties caused addition suggest that variation works favor enhancement demixing solution, but rheological induces opposite trend, or delay demixing. When immersion coagulation into bath, solidified structural functional indicate cast affected trade-offrelationship between hindrance. With small amount driving force played major role on solution demixing, inducing enhancement, corresponding to acceleration separation due PVP's nonsolvent effect. Consequently, acts enhancer, resulting both macropore enlargement permeate flux increase. more PVP, however, structure permeability suppressed rather than enlarged increased. These phenomena reflect delayed, with hindrance offsetting for enhancement.