Enhancing optical properties and antimicrobial efficacy of PEO/CS-doped TiO₂ nanoparticles for food packaging applications

Utilizing the solution casting technique, polymer nanocomposites (PNCs) films including polyethylene oxide and chitosan (PEO/CS) doped with titanium dioxide nanoparticles (TiO₂ NPs) as nanoceramic were successfully synthesized. The study investigated how varying TiO₂ nanoparticle concentrations influenced the structural, optical properties, and antibacterial activity of the polymeric matrix. XRD patterns revealed an increase in the amorphous nature of the polymer blend as the content of TiO₂ NPs inside the PEO/CS blend grew. The FT-IR analysis confirmed the interaction between TiO₂ NPs and the PEO/CS blend. This confirmation is attributed to the observed vibrational changes upon the incorporation of TiO₂ dopant into the polymer matrix. The UV–visible spectrum aided in the determination of optical energy band gaps (both direct and indirect), showing reductions in both E_gd and E_gin with higher TiO₂ concentrations. SEM highlighted the partial compatibility between PEO/CS and TiO₂, while transmission electron microscopy depicted spherical TiO₂ NPs with diameters ranging from approximately 9 to 25 nm. Antimicrobial assessments indicated heightened efficacy in all nanocomposite samples compared to the pure PEO/CS composite, with a linear correlation to the quantity of TiO₂ nanoparticles present. These findings strongly suggest the potential of these nanocomposites for food packaging applications.