Nanofiller controllable optical parameters and improved thermal properties of (PVP/PEO)/Al2O3 and (PVP/PEO)/SiO2 nanocomposites

The optical and thermal characterizations of poly(vinyl pyrrolidone) (PVP)/poly(ethylene oxide) (PEO) blend matrix having gamma-phase alumina (Al2O3) and amorphous silica (SiO2) nanoparticles-based polymer nanocomposite (PNC) films i.e., (PVP/PEO)/Al2O3 and (PVP/PEO)/SiO2 are reported. The ultraviolet-visible (UV-vis) absorbance spectra of these biodegradable nanocomposite materials evidenced significant absorbance which is mainly due to the PEO amount in the blend matrix. Furthermore, the absorbance increased slowly with the decrease of photons wavelength in the visible range and thereafter relatively faster in the UV-range, following a strong absorbance band which is ascribed to electronic transitions in the polymers structures. Also, an increase in absorbance and a redshift of electronic transition band was observed with the increase of Al2O3 and SiO2 concentrations (1-5 wt%) in these nanocomposites. It was observed that the increase of both the Al2O3 and SiO2 contents created polymers structural disordering which caused a gradual decrease in energy band gaps whereas Urbach energy, refractive index, and optical conductivity of these PNC materials increased. Differential scanning calorimetry (DSC) thermograms of these films confirmed a considerable increase in melting temperature and degree of crystallinity of the PNC materials in comparison to the host PVP/PEO blend matrix. Finally, considering the optical parameters, specific applications of these thermally improved nanocomposites such as nanofiller concentration controllable UV-vis absorber, optical band gap tuner, and enhanced optical conductor for advances in optoelectronics are highlighted.

Automated summary

This study reported the optical and thermal characterizations of PVP/PEO blend matrix-based PNC films, showing significant absorbance in the UV-vis spectra mainly due to the PEO content. As the concentrations of Al2O3 and SiO2 increased, absorbance and redshift of electronic transition band were observed.