Preparation, characterization, and the antimicrobial activity of PVA-PVP/ZnO nanofiber films via indigenous electrospinning setup

The study aimed to produce composite nanofibers (NFs) using the electrospinning method from Polyvinyl alcohol- Polyvinylpyrrolidone/Zinc oxide (PVA-PVP/ZnO) solutions. X-ray diffraction analysis confirmed that in the composite nanofibers, the relative intensity of the dominant crystal plane (101) associated with the wurtzite hexagonal structure of ZnO nanoparticles (NPs) decreased, and its broadness increased in the composite, indicating the presence of an amorphous part in the sample. The existence of functional groups from polymer systems was confirmed by Fourier-transform infrared spectroscopy (FTIR) spectral analysis. Field emission scanning electron microscope (FESEM) images revealed linear and branched uniform nanofiber structures with smooth surfaces of PVA-PVP/ZnO electrospun. The absorbance of PVA-PVP/ZnO NFs increased with the increase in ZnO NPs content, and an absorption band was observed in the ultra violet (UV) region at around 310 nm. The calculation of the optical energy gap using the absorption spectra fitting (ASF) approach roughly aligned with Tauc's model, ranging from 3.47 to 3.24 eV. The highest inhibition zone (14 and 15 mm) was observed at the ratios of 4 and 6 wt.% of ZnO NPs against gram-negative bacteria (Escherichia coli).