Gamma-rays irradiated ZrCeO4NPs/chitosan nanocomposites: correlation between structure and physical properties

This study explores the enhancement of dielectric, thermal, and structural properties of chitosan-polyvinyl alcohol (CS-PVA) nanocomposites through the incorporation of zirconium cerium oxide (ZrCeO₄) nanoparticles (NPs) and subsequent gamma irradiation treatments. A series of ZrCeO₄NPs/CS-PVA films were prepared via solution casting with varying nanoparticle concentrations (1%, 2%, and 3% by weight) and irradiated at gamma doses of 5, 15, and 25 kGy. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed strong interfacial interactions and modifications in the crystalline structure of the CS-PVA matrix upon nanoparticle additions. Scanning electron microscopy (SEM) demonstrated homogeneous dispersion of ZrCeO₄NPs within the matrix, leading to a denser structure and smoother surface morphology at higher nanoparticle concentrations. Thermogravimetric analysis (TGA) revealed improved thermal stability with increasing ZrCeO₄NPs contents, indicating enhanced material resistance to decomposition. Dielectric measurements showed that the real part of the dielectric constant (ε') significantly increased at lower frequencies, especially for nanocomposites irradiated at 15 kGy, suggesting an optimal balance between interfacial polarization and matrix integrity. A marked reduction in dielectric loss (ε'') with increasing frequency was observed, attributed to limited dipole reorientation at higher frequencies. The relaxation time and activation energy, derived from frequency-dependent tangent loss data, demonstrated that gamma irradiation optimizes dielectric performance by modulating relaxation mechanisms within the nanocomposites. The combined effects of ZrCeO₄Nps and gamma radiation provide a novel route for tuning the dielectric properties of CS-PVA composites, making them highly suitable for advanced dielectric applications in flexible electronics, sensors, and energy storage devices.