Structural and Optical Optimization of SiC Nanotube-Reinforced PVP Nanocomposites for Advanced Functional Applications

Silicon carbide (SiC)-based polymer nanocomposites have attracted significant attention for advanced electromechanical and optoelectronic applications due to their thermal stability, mechanical robustness, and tunable electronic properties. In this study, one-dimensional SiC nanotubes were successfully synthesized via a high-temperature carbothermal method at 1800 °C and subsequently incorporated into a polyvinylpyrrolidone (PVP) matrix to fabricate SiC/PVP nanocomposites with filler concentrations ranging from 1 to 5 wt%. The structural, morphological, and optical properties of the composites were systematically investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and UV–Vis spectroscopy.

SEM observations confirmed the hollow nanotube structure and rough surface morphology of SiC, while XRD analysis revealed the formation of the cubic 3C-SiC phase and its effective incorporation into the amorphous PVP matrix. At low filler loadings (1–3 wt%), SiC nanotubes were homogeneously dispersed, leading to reduced crystallite sizes, increased microstrain, and higher dislocation densities due to enhanced interfacial interactions and lattice distortion. In contrast, at 5 wt% SiC, aggregation effects became dominant, resulting in increased crystallite size and reduced lattice defects. Optical measurements demonstrated a non-linear band gap behavior, with a minimum value of 5.51 eV observed at 3 wt% SiC/PVP, attributed to interface-induced defect states and enhanced electronic interaction. FTIR spectra further confirmed strong interfacial bonding between SiC surface groups and PVP functional groups.

Based on the combined structural and optical analyses, an optimal filler concentration of approximately 2 wt% was identified, offering balanced crystallinity, defect density, and band gap tunability. These findings highlight the potential of SiC/PVP nanocomposites as promising materials for high-performance optoelectronic and dielectric components in advanced engineering systems.