Structural, optical, and dielectric modulus properties of PEO/PVA blend filled with metakaolin

The PEO/PVA blend incorporated by different weight percentages (≤10%) of metakaolin (MK) has been prepared and characterised. The XRD revealed a semicrystalline structure of pure PEO/PVA with peaks indicating the presence of silicon and aluminum in the MK composition. The addition of MK in the blend leads to a decrease in the diffraction peak intensities, confirming that the blend-MK interactions break some PEO/PVA blend domains. The UV–Vis transmittance and reflectance spectra were studied and used to determine optical parameters. The decrease in the band-gap values was demonstrated with the increase in MK to confirm the suitability of MK as a band-gap regulated the optical material in different applications. The obtained values of the optical band gap decrease with the increase of MK concentration due to the defect levels that correlate to the sample's density of localized states. The higher values of ε′ found at a lower frequency related to the effect of the dominant contribution of the interfacial polarization due to the accumulation of charges, whereas the higher values of ε″ at the lower frequency were related to an increase in the energy loss in the composite films. The Cole-Cole plot displays semicircles at the lower frequency range with a linear increase at the intermediate and higher frequency due to the grain boundary and the relaxation process. The values of the real part (σ′) are lower than that of the corresponding values of the imaginary part (σ″). Applied an electric field causes polarized films and the ability to store an electric charge. Therefore, these composites may be used in flexible capacitors.