Electrospun fibers of poly (vinyl alcohol): zinc acetate (PVA:AcZn) and further ZnO production: evaluation of PVA:AcZn ratio and annealing temperature effects on ZnO structure

Abstract

The effects of the poly (vinyl alcohol): zinc acetate (PVA:AcZn) mass ratio on the morphology and structure of the precursor electrospun fibers as well as the calcination conditions on the morphology and chemical and physical structure of the as-obtained zinc oxide (ZnO) nanofibers are deeply discussed in this work. Initially, precursor nanofibers were obtained through electrospinning, a simple and accessible process for the production of materials in nano- and sub-micrometric scales, of aqueous solution of poly (vinyl alcohol) (PVA) and zinc acetate (AcZn) in the mass ratios PVA:AcZn 1:0.5, 1:1, and 1:2. In the sequence, the precursor nanofibers were calcined (500, 600, and 700 °C, for 2 h in atmospheric air) to obtain the ZnO fibers. The precursor PVA:AcZn and the ZnO fibers were characterized through Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), X-ray diffractometry (XRD), X-ray scattering spectroscopy (EDS), Raman spectroscopy, and scanning electron microscopy (SEM). The set of results indicates that the ZnO fibers with the best characteristics (homogeneity in morphology, smaller average diameter, organization of the crystalline structure, among others) were obtained using mass ratio of PVA:AcZn 1:1 and calcination at 600 °C for 2 h in atmospheric air.