Hybrid Ethylcellulose Polymeric Films: Ag(I)‐Based Components and Curcumin as Reinforcing Ingredients for Enhanced Food Packaging Properties

Abstract

Bio‐active ethylcellulose (EC) polymeric films have been obtained by incorporating curcumin (curc) and Ag(I)‐based compounds, known for their antioxidant and antimicrobial activity, respectively, within the polymeric matrix. The recently reported Ag(I) coordination polymer, in both its structural forms (α‐[(bpy)Ag(OTf)]∞ and β‐{[(bpy)Ag][OTf]}∞), and the [(bpy)Ag(OTf)]∞‐curc polymeric co‐crystal (bpy = 2,2’‐bipyridine; OTf = trifluoromethanesulfonate) have been selected as Ag(I) species. The hybrid composite films have been prepared through the simple solvent casting method and characterized through Powder X‐Ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM), UV‐vis spectroscopy. The deep investigation of the film samples highlighted the non‐inert behaviour of EC towards these specific active ingredients. Antimicrobial tests showed that EC films embedding the Ag(I)‐based compounds present good antimicrobial performance, in particular against Staphylococcus aureus, used as a model of Gram‐positive bacteria. In addition, Silver migration tests, performed on the Ag(I)‐incorporating EC films, evidenced low values of silver release particularly in the case of the EC films incorporating [(bpy)Ag(OTf)]∞‐curc.