Production of Uniform Electrospun 2-Cyanopyridinium Salicylate – Polyvinyl Alcohol Nanofibersusing Cylindrical Bar Collector for Nonlinear Optical Applications

Abstract

The electrospinning technique was used to synthesize nanofibers of organic 2-cynopyridinium salicylate (2-CPSC) molecules embedded in polyvinyl alcohol (PVA) polymer using both a drum collector and an indigenously made parallel bar cylindrical collector unit. The microscopical analysis was performed for the preliminary morphological study of the collected nanofibers using both a drum collector and a parallel bar collector. Scanning electron microscopic (SEM) analysis confirmed the formation of smooth, clear, cylindrical shape, and highly homogenous 2-CPSC – PVA nanofibers collected from the parallel bar collector unit compared to the drum collector, and these homogenous nanofibers were selected for further characterization. X-ray diffraction (XRD) study demonstrates the preferred crystallographic orientation of organic 2-CPSC molecules inside the host PVA polymer. The synthesized nanofibers were characterized using Fourier Transform Infrared (FTIR) Spectroscopy to confirm the presence of different molecular vibrations. Using ultraviolet-visible (UV-Vis) spectroscopic analysis, the complete transparency of the 2-CPSC – PVA nanofiber throughout the visible region is observed, and from Tauc's plot, the obtained optical band gap energy (E_g) is 5.24 eV. The Z-scan technique was employed to investigate the nonlinear absorption coefficient (β), nonlinear refractive index (n₂), and third-order nonlinear susceptibility ($$ ).