Effect of titanium oxide on structural and optoelectrical properties of PLA/PEG/graphene nanocomposite films

Abstract

The effects of small loadings (up to 0.5 wt%) of titanium oxide (TiO₂) nanoparticles on structural, morphological, chemical, wetting, and optoelectrical properties of the polylactic acid/polyethylene glycol/graphene nanoplatelets (PLA/PEG/GNPs) nanocomposites have been investigated. The solution casting technique was adopted to fabricate the PLA/PEG/GNPs/TiO₂ nanocomposite films, and advanced characterization techniques were used to examine the loading effects of TiO₂ nanoparticles. X-ray diffraction showed semicrystalline nature, surface morphology showed good dispersion of GNPs and TiO₂ nanoparticles, and the elemental analysis showed the purity of the nanocomposite films. Surface wetting properties were modified significantly from hydrophilic to hydrophobic (42.57° to 76.25°). Substantial enhancements were observed in the optical properties of the fabricated PLA/PEG/GNPs nanocomposite films after the incorporation of TiO₂ nanoparticles including direct bandgap (5.10–3.46 eV), indirect bandgap (4.66–2.99 eV), refractive index (1.85–2.51 at 300 nm), and optical conductivity (6.25×10¹⁰ to 2.65×10¹¹ S cm⁻¹ at 300 nm). There was an excellent rise in dielectric constant (126.4–166.9 at 4 MHz), a good drop in dielectric loss (16.9–13.2 at 4 MHz), and a reasonable enhancement in AC conductivity (2.9 ×10⁻³ to 3.8 ×10⁻³ at 4 MHz). Incorporating TiO₂ nanoparticles into the PLA/PEG/GNPs nanocomposites makes them suitable candidates for flexible optoelectronic devices.