Fabrication and characterization of high flux poly(vinylidene fluoride) electrospun nanofibrous membrane using amphiphilic polyethylene-block-poly(ethylene glycol) copolymer

Electrospun nanofiber membranes (ENM) made of polymers such as polysulfone and poly(vinylidene fluoride) (PVDF) have a much higher contact angle (CA) and also more hydrophobic when compared to the virgin polymers. For water treatment applications, membranes with hydrophilic nature are highly desirable in order to achieve high flux and less fouling potentials. Hence, in the present study, highly hydrophilic electrospun nanofiber membranes (ENMs) were prepared by blending PVDF polymer with amphiphilic polyethylene-block-poly (ethylene glycol) (PE-b-PEG) copolymer. Resulting amphiphilic ENMs were highly porous (77%-92%) and the breaking elongation of 140% with a young's modulus of 2.55 MPa was observed. When compared with the control PVDF membrane, PE-b-PEG blended ENMs revealed higher water permeation flux owing to the enrichment of the hydrophilic PEG segments at the membrane surface, which was confirmed by using X-ray photoelectric spectroscopy and Energy-dispersive spectroscopy measurements. When compared to the phase inversion process (CA of 97.3 degrees) blended ENM had CA of 0 degrees, which indicates that besides hydrophilic block copolymer segments, the nature of membrane formation also contributes its role in influencing the hydrophilicity of the membrane. This improved hydrophilicity in combination with larger pore sizes of the PVDF/ PE-b-PEG membranes have contributed to enhancement of pure water flux, protein solution permeability and water flux recovery, which can be applied potentially for water treatment applications.

Automated summary

In this study, highly hydrophilic electrospun nanofiber membranes were prepared by blending PVDF polymer with amphiphilic polyethylene-block-poly(ethylene glycol) copolymer, resulting in higher water permeation flux. The membrane's properties and formation process contribute to its hydrophilicity, and the combination of improved hydrophilicity and larger pore sizes may enhance pure water flux for potential water treatment applications.