Hydrophilic modification of poly(vinylidene fluoride) membrane with poly(vinyl pyrrolidone) via a cross-linking reaction

A highly hydrophilic hollow fiber poly(vinylidene fluoride) (PVDF) membrane [PVDF-cl-poly(vinyl pyrrolidone) (PVP) membrane] was prepared by a cross-linking reaction with the hydrophilic PVP, which was immobilized firmly on the outer surface and cross-section of the PVDF hollow fiber membrane via a simple immersion process. The cross-linking between PVDF and PVP was firstly verified via nuclear magnetic resonance measurement on PVP solution after cross-linking. The hydrophilic stability of the modified PVDF membrane was evaluated by measuring the pure water flux after different times of immersion and drying. The anti-fouling properties were estimated by cyclic filtration of protein solution. When the cross-linking time was as long as 6 hr and the PVP content reached 5 wt %, the pure water flux (J _v) was constant as ∼ 600 L m ^-2 hr ^-1. The hydrophilicity of the PVDF-cl-PVP membrane was significantly enhanced and exhibited a good stability. The PVDF-cl-PVP membrane showed an excellent anti-protein-fouling performance during the cyclic filtration of bovine serum albumin solution. Therefore, a highly hydrophilic and anti-protein-fouling PVDF hollow fiber membrane with a long-term stability can be prepared by a simple and economical cross-linking process with PVP.