Design of chitosan‐ g ‐poly(2‐hydroxyethyl acrylate)‐based hybrid nanocomposite films containing zinc oxide nanoparticles and poly(vinyl alcohol) with improved antibacterial and mechanical properties

Four chitosan‐based films, namely pure chitosan (CS), chitosan‐ g ‐poly(2‐hydroxyethyl acrylate) (CS‐ g ‐PHEA), ZnO nanoparticle‐loaded CS‐ g ‐PHEA (ZnO NPs‐loaded CS‐ g ‐PHEA), and poly(vinyl alcohol)‐containing ZnO NPs‐loaded CS‐ g ‐PHEA (ZnO NPs‐loaded CS‐ g ‐PHEA/PVA), were successfully fabricated using a solvent‐casting method. CS‐ g ‐PHEA was synthesized via free‐radical graft copolymerization of CS with 2‐hydroxyethyl acrylate, using ammonium persulfate as the initiator and N , N ′‐methylenebis(acrylamide) as the crosslinker, followed by ultrasonication. ZnO NPs and, where applicable, PVA were subsequently incorporated into the grafted polymer matrix prior to solvent casting. The synthesized composite films were smooth, transparent, and homogeneous, with an average thickness of approximately 0.05 mm, indicating uniform film formation. The structure, morphology, crystallinity, thermal degradation behavior, and mechanical properties of the films were investigated using Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), energy‐dispersive X‐ray fluorescence spectroscopy, X‐ray diffraction (XRD), thermogravimetric analysis, and tensile testing. The tensile strength increased substantially from 15.5 MPa for the CS film to 40.0 MPa for the ZnO NPs‐loaded CS‐ g ‐PHEA/PVA film, demonstrating the reinforcing effect of ZnO NPs and PVA. XRD analysis revealed a decrease in the crystallinity index from 61.8% for pure CS to 40.6% for the ZnO NPs‐loaded CS‐ g ‐PHEA/PVA film, indicating structural modification of the CS matrix. The water contact angle decreased from 101.37° for the pure CS film to a minimum of 67.04° for the ZnO NPs‐loaded CS‐ g ‐PHEA film, indicating improved surface wettability. The ZnO NPs‐loaded CS‐ g ‐PHEA film exhibited the highest antibacterial activity, with inhibition zones of 20 mm against Staphylococcus aureus and 16 mm against Escherichia coli . These findings demonstrate that the developed hybrid nanocomposite films exhibit improved mechanical performance, improved surface wettability, and enhanced antibacterial activity, making them promising candidates for wound dressing applications.