Role of ethyl acetate concentration and needle size in tailoring electrospun nanofiber structure

This study examines the impact of ethyl acetate addition on the morphology and diameter of nanofibers during electrospinning. Solutions containing polyacrylonitrile, high-entropy oxide, and dimethylformamide (DMF) were prepared, with ethyl acetate added at 5%, 10%, and 15% ratios relative to DMF. Electrospinning was performed under a 0.14 mL/h feed rate, 6 kV voltage, 205 mm distance, and 500 rpm rotation speed. Continuous and uniform nanofibers were obtained using 10% ethyl acetate, with diameters as low as 110 nm. At 15%, morphology was disrupted due to decreased viscosity, while 5% and 10% ratios yielded thinner, more homogeneous fibers. A solution with 5% PAN, 35% high-entropy oxide, and 10% ethyl acetate was electrospun using 16G and 22G nozzles, resulting in fibers with diameters of 182 nm and 111 nm, respectively. SEM analysis confirmed diameter differences, while XRD showed no significant structural changes with varying ethyl acetate content. FTIR spectra revealed characteristic peaks of high-entropy oxides, indicating the successful incorporation of these oxides into the nanofibers.