Poly (ethylene furanoate)/poly (ethylene terephthalate) blend electrospun fibrous membranes for oil-in-water emulsification

• Sustainable PEF-based electrospun membranes developed for O/W emulsification • Partial miscibility of PEF/PET confirmed by single shifted T g • Blend membranes exhibit enhanced mechanical, thermal and chemical stability • PEF-based membranes outperform SPG in submicron droplet size Premix membrane emulsification (PME) enables the production of fine, narrowly distributed emulsions under mild conditions. This study reports the fabrication of electrospun fibrous membranes (EFMs) made from biobased poly(ethylene furanoate) (PEF), petroleum-based poly(ethylene terephthalate) (PET), and a 1:1 PEF/PET blend, and investigates how their morphology and physicochemical properties govern PME performance. The EFMs consist of defect-free, randomly oriented fibers, with median diameters of ∼2.2 µm (PET), 1.4 µm (PEF), and 1.6 µm (PEF/PET blend). The single glass transition temperature (T g ) of the PEF/PET blend, with a significant shift, confirms the partial miscibility of the blend. The PEF/PET blend EFM has shown improved mechanical, thermal, and chemical properties compared to neat PET or PEF EFMs. Electrospinning-induced roughness renders all EFMs hydrophobic, yet the blend shows the lowest water contact angle (∼115°) and, together with its larger effective pore size (∼13 µm), delivers the highest water flux (3 × 10 5 -7.5 × 10 5 L m -2 h -1 at 100-500 kPa) with the lowest hydraulic resistance. In PME of oil-in-water emulsions, repeated passes (up to five) through the EFMs reduce droplet sizes to the submicrometer range, with final Sauter mean diameters of 0.67 ± 0.31 µm (PET), 0.31 ± 0.02 µm (PEF), and 0.46 ± 0.03 µm (PEF/PET), outperforming a commercial Shirasu Porous Glass membrane (0.86 ± 0.21 µm). Viscosity-dependent studies using different oils further demonstrate the versatility of PEF-based membranes. This study opens a new avenue for PME using sustainable PEF and highlights its efficacy in producing fine emulsions.