Electrospinning of fouling-resistant non-woven fibrous filtration membranes from PVDF/Polyampholyte blends

Poly (vinylidene fluoride) (PVDF) is widely used in filtration and waste-water treatment applications due to its excellent mechanical, chemical, and thermal stability. However, its inherent high hydrophobicity leads to membrane fouling. One way to increase fouling resistance is to improve the hydrophilicity of PVDF-based membranes through blending with more hydrophilic polymers. Our research investigates blends of PVDF with polyampholytes, amphoteric macromolecules with positive and negative ionic groups showing excellent hydrophilicity. Fouling resistant non-woven fibrous membranes were fabricated using electrospinning of PVDF and a random polyampholyte copolymer (r-PAC) blended at different concentrations. r-PAC is synthesized by randomly co-polymerizing three monomers that are either hydrophobic (2,2,2-trifluoroethyl methacrylate); positively charged ([2-(methacryloyloxy) ethyl]trimethylammonium chloride); or negatively charged (methacrylic acid). The obtained fiber mats were characterized by wide angle X-ray scattering, Fourier-transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. Sessile drop contact angle measurements were used to evaluate the surface wettability of the membranes. Membrane fouling was assessed by fluorescent Bovine Serum Albumin (BSA) absorption tests.