Correlation of SiC content with structural, optical, and dielectric characteristics in PVA-based nanocomposites: a comprehensive study

Abstract

Polyvinyl alcohol (PVA) is a flexible, biocompatible polymer, but its low thermal stability and mechanical strength limit its advanced applications. To address this, nanosized silicon carbide (SiC) was incorporated into the PVA matrix at varying concentrations (1–10 wt%) to enhance its structural, optical, morphological, and dielectric properties. The SiC/PVA nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–Visible (UV–Vis), Raman spectroscopies, and dielectric measurements. XRD confirmed the 3C-SiC phase with crystallite sizes of 13.84 nm (Williamson–Hall) and 39.23 nm (Debye–Scherrer). SEM revealed nanowires and fine crystallites. Raman analysis gave a crystallinity ratio (I(TO/LO)) of 1.32 for pure SiC. The optical band gap decreased with increasing SiC content due to enhanced filler–matrix interaction but became inconsistent at higher concentrations (7–10 wt%) due to excessive dispersion. Dielectric studies showed that 7 wt% SiC provided the highest dielectric constant at low frequencies and elevated temperatures, attributed to Maxwell–Wagner–Sillars polarization. These findings suggest that 7 wt% SiC is the optimal loading for improved dispersion and performance. The enhanced properties make SiC/PVA nanocomposites promising for applications in flexible electronics, dielectric devices, high-temperature sensors.

Graphical Abstract