Enhanced UV shielding in PLA/PS–BaTiO3 nanocomposite films: Optical, dielectric, and conductivity insights
Faisal Alotaibi, A. Rajeh, M. O. Farea, Ahmed Elgarayhi, Asmaa M. Elzayat, W.M. Awad, E.M. Abdelrazek
Abstract
• Significant UV shielding enhancement was achieved by incorporating 2–8 wt% BaTiO 3 nanoparticles into PLA/PS films, resulting in a strong red-shift and intensified UV absorption. • Optical band gap reduction from 3.84 → 3.23 eV (direct) and 3.39 → 2.78 eV (indirect) confirms the formation of charge-transfer complexes and defect-state-assisted photon trapping. • AC conductivity improved by six orders of magnitude (10 −17 → 10 −11 S/cm), demonstrating enhanced ion mobility and non-Debye relaxation behavior. • Structural compatibility and uniform BaTiO 3 dispersion, evidenced by XRD, FTIR, and SEM, confirmed the formation of a stable hybrid network suitable for UV-protective coatings and optoelectronic packaging. This work reports the successful fabrication of PLA/PS–BaTiO 3 nanocomposite films with significantly enhanced UV protection capabilities. BaTiO 3 nanoparticles (2–8 wt%) were incorporated into a PLA/PS matrix via solution casting, and their influence on optical and dielectric properties was systematically evaluated. XRD analysis confirmed the formation of BaTiO 3 with an estimated crystallite size of ∼ 57 nm according to the Scherrer equation, indicating a well-defined nanoscale structure. UV–Vis spectroscopy revealed a pronounced increase in UV absorption intensity accompanied by a clear red-shift in the absorption edge with rising BaTiO 3 content. This strong UV attenuation is attributed to charge-transfer interactions between BaTiO 3 and polymer functional groups, which introduce additional defect states that facilitate photon trapping. The reduction of the direct optical band gap from 3.84 eV to 3.23 eV and the indirect band gap from 3.39 eV to 2.78 eV at 8 wt% BaTiO 3 loading, highlighting the extent of enhancement in UV attenuation. Complementary FT-IR, XRD, and SEM analyses confirmed structural compatibility and uniform nanofiller dispersion, which contribute to improved interfacial polarization and charge transport. Dielectric and electric modulus studies verified non-Debye relaxation behavior and enhanced ion mobility, supporting the superior energy dissipation capability of the nanocomposites under UV exposure. Overall, the combined optical and electrical features establish PLA/PS–BaTiO 3 nanocomposites as highly promising materials for UV-shielding films, protective coatings, and optoelectronic packaging applications.