Improving the optical, thermal, mechanical, electrical properties and antibacterial activity of PVA-chitosan by biosynthesized Ag nanoparticles: Eco-friendly nanocomposites for food packaging applications.

In this study, nanocomposite films were produced by blending polyvinyl alcohol (PVA) and chitosan (Cs) polymers with 70 % PVA and 30 % Cs, incorporating silver nanoparticles (Ag NPs) via a solution-casting method. The research aims to investigate the impact of the biosynthesized Ag NPs by Chenopodium murale leaf extract on optical, morphological, mechanical, thermal, electrical, and antibacterial properties. XRD analysis showed a decrease in crystallinity degree with Ag NPs addition. TEM revealed Ag NPs in cubic and spherical shapes with an average size of 23.4 nm. SEM and AFM indicated surface morphology changes. FT-IR spectra showed interaction between Ag ions and the blend. The energy gap decreased with increasing Ag NPs concentration. TGA exhibited enhanced thermal stability. Mechanical properties improved significantly. AC electrical conductivity and dielectric parameters were studied. Antibacterial activity against Gram-positive and Gram-negative bacteria was observed. Overall, PVA/Cs-Ag NPs films show promise for food packaging and optoelectronic applications.

MoO3 nanoplates reinforced the structural, electrical, mechanical, and antibacterial characteristics of polyvinyl pyrrolidone/sodium alginate polymer blend for optoelectronics and biological applications.

Organic/Inorganic nanostructures enable the development of new functional materials for optoelectronics and biological applications. In this work, nanocomposite films of polyvinyl pyrrolidone (PVP) and sodium alginate (NaAlg) blend matrix (30/70 wt%) filled with molybdenum trioxide (MoO3) nanoplates were prepared using solution casting procedure. The effect of MoO3 nanoplates on structural, optical, electrical and antibacterial characteristics of pure PVP/NaAlg blend was investigated. The sizes of MoO3 nanoplates had dimensions between 90 and 420 nm with orthorhombic phase as indicated by the TEM and XRD techniques. Also, the XRD patterns of filled films suggested that the presence of crystalline phases of MoO3 within PVP/NaAlg matrix. FTIR analysis revealed the primary vibrational peaks of PVP and NaAlg, whose strength altered randomly after filling. The UV absorption increased gradually and shifted to the higher wavelength side. The alternating current (AC) conductivity and dielectric parameters were improved with increasing MoO3 concentration. The antibacterial activity against Staphylococcus aureus and Escherichia coli increased with increase of MoO3 nanoplates concentration. The filled PVP/NaAlg-MoO3 samples displayed considerable enhancements in the values of Young's modulus (Y), tensile stress (σt) and elongation at break (εB). The obtained results imply that these nanocomposite films can be potentially used in optoelectronics and biological applications.