Electrospinning Versus Solvent Casting Approach to Fabricate Tailored PES/SPES/PVP Membranes of Next Generation

This study explored the potential of blending poly-(ether sulfone)/disulfonated poly-(ether sulfone) (PES/SPES) at various weight ratios with and without polyvinylpyrrolidone (PVP) to enhance the membrane properties for potential applications like fuel cells, water treatment, and lithium-ion battery separators. SPES was appropriately synthesized as a copolymer constituted of alternated unsulfonated (ES) and disulfonated (SES) sequences, achieving a degree of sulfonation of about 100%. SPES improved the membrane's hydrophilicity, while PVP acts as compatibilizer of PES/SPES blends and pore creator. For comparison purposes, two different approaches were exploited for membrane fabrication: casting and electrospinning techniques. The membranes were characterized using various techniques to evaluate thermal stability, hydrophilicity, uptake behavior, morphology, and microstructure. SEM images revealed that the SPES content and PVP incorporation significantly influenced membrane morphology and porosity. Water uptake increased with SPES content, while methanol uptake was less affected. PVP enhanced both water and methanol uptake in the solvent-cast membranes. Electrospun membranes exhibited higher uptake due to their increased porosity and surface area. Contact angle measurements confirmed that SPES improved hydrophilicity and surface roughness played a crucial role. TGA analysis showed that PES membranes had the highest thermal stability, while SPES decreased it. DSC analysis revealed that PVP acted as a compatibilizer in solvent-cast membranes but not in electrospun ones. The study demonstrated that both blend composition and fabrication techniques could be tailored to optimize membrane properties for specific applications. The findings provide valuable insights for developing advanced membranes with an enhanced performance.