Electrospun tungsten oxide NPs/PVA nanofibers: A study on the morphology and Kramers–Kronig analysis of infrared reflectance spectra

The major objective of this work is focused on the preparation and characterization of poly (vinyl alcohol) (PVA) embedding tungsten oxide nanoparticles based on electrospinning technique. A surfactant (CTAB) was introduced to incorporate tungsten oxide nanoparticles into the PVA nanofibers homogeneously. To prepare a viscous solution of PVA nanofiber containing tungsten oxide nanoparticles, the distance between the tip of the needle and the surface of the foil was chosen as 10 and 15 cm. The tungsten oxide NPs/PVA composite nanofibers have been characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and reflectance spectrum in the wave length range of 200–1200 nm. Fiber diameters decrease with increasing of tip-to-collector distance from 10 to 15 cm. The average diameters were estimated about 165±30 nm and 145±30 nm from scanning electron microscopy at 10 and 15 cm, respectively. The optical properties of the electrospun nanofibers were examined by the Kramers–Kronig model. The optical results show that tungsten oxide nanopowder show almost five times higher conductivity, lower absorbance and zero band gap energy.