Synthesis, characterization, and application of metal-free sulfonamide-vitamin C adduct to improve the optical properties of PVA polymer

Abstract

Improving optical properties is an important topic in the field of polymer science. In this research, a novel, metal-free, and inexpensive vitamin C sulfonamide adduct has been developed to enhance the optical behaviors of polyvinyl alcohol (PVA). Initially, the vitamin C adduct has been fabricated through atom economic reaction and then characterized using several spectroscopic techniques, including 1 H NMR, 13 C NMR, DEPT-135, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Accordingly, a dramatic chemical alteration in ascorbic acid structure has been confirmed and led to enhancing chemical interactions with the host polymer. The ascorbic acid adduct has been doped into PVA to prepare a flexible film of polymer composites with potential optical behaviors. The identity of composite film has specified from FTIR, XRD, and UV–vis spectroscopy. The XRD pattern of the hybrid polymer has revealed a remarkable boost in its amorphous structure compared to the PVA host. The FTIR data of both matrix PVA and its composites reveal the potent chemical interactions of functional groups within the hybrid PVA. The main optical information of synthesized hybrid film was obtained from the UV–vis spectra. The refractive index ( n ) and dielectric loss ( ε i ) values are elevated notably, whereas the optical band gap energy (E g ) declined from 6.3 to 3.6 eV. The direct electronic transition between the valence band (VB) and conduction band (CB) was determined by implementing Tauc’s model. These preliminary results suggest that the fabricated flexible composite will have an excellent opportunity to use in the manufacturing optical devices.