Recent Progress in Enhanced Optical, Mechanical, Thermal Properties, and Antibacterial Activity of the Chitosan/Polyvinylalcohol/Co₃O₄ Nanocomposites for Optoelectronics and Biological Applications

The present study explores the influence of Cobalt oxide nanoparticles(Co₃O₄ NPs) on the physicochemical characteristics of Poly(vinylalcohol)/ Chitosan (PVA/Cs) blend. Using a variety of techniques, the pure blend and the nanocomposites’ composition, structure, optical, thermal, and mechanical properties, and antibacterial activity were characterized. The Co₃O₄ NPs were produced by precipitation method utilizing cobalt salt as the raw material. The crystalline nature of the nanoparticles and semi-crystalline behavior of the PVA/Cs are demonstrated by the XRD data. Adding nanoparticles to the pure blend reduced the intensity of the semi-crystalline. The rise in absorption intensity observed in UV-visible spectra upon the incorporation of Co₃O₄ NPs into the PVA/Cs blend indicates an improved dispersion of the nanoparticles within the blend. When Co₃O₄ NPs are added, the energy band-gap E_gdir and E_gind of PVA/Cs–Co₃O₄ samples greatly decrease. According to TGA data, the thermal stability of nanocomposites was significantly higher than that of the PVA/Cs blend, and it rose as the concentration of nanoparticles increased. When compared to neat PVA/Cs film, mechanical property investigation of PVA/Cs–Co₃O₄ nanocomposites films revealed enhanced features. The effectiveness of the PVA/Cs–Co₃O₄ nanocomposite films in inhibiting the growth of microorganisms was assessed by evaluating their antimicrobial activity (ANMAC) against a range of bacteria and fungi. The inclusion of Co₃O₄ NPs led to an increase in activity against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria as well as fungi Candida albicans and Aspergillus niger (C. albicans and A. niger). The addition of Co₃O₄ NPs to the PVA/Cs blend effectively improved the material’s optical, thermal, mechanical, and antibacterial properties. This remarkable improvement stems from the Co₃O₄ NPs, which were introduced into the PVA/Cs blend in different amounts, leading to the development of novel nanocomposites. The outstanding properties of Co₃O₄/PVA/Cs nanocomposite films suggest their potential for applications in optoelectronics and food packaging.