The multifunctional polyvinyl alcohol based diethyl ferulate nano silver film with UV-blocking and antibacterial properties

Food is prone to spoilage due to light and microbial exposure. To address this issue, Polystyrene microspheres @ Polydopamine / Diethyl ferulate / AgNPs (PS@PDA/DEF/Ag) was synthesized via copper-catalyzed azide/alkynyl cycloaddition reaction (CuAAC) and in-situ reduction. Subsequently, it was incorporated into a polyvinyl alcohol (PVA) matrix to fabricate PS@PDA/DEF/Ag/PVA multifunctional films. Derivative thermogravimetric (DTGA) analysis showed the exothermic peak of PS@PDA/DEF/Ag/PVA-4 wt% increased from 265.3 °C to 334.5 °C compared with PVA film. At concentrations exceeding 0.5 wt%, the UV shielding rate of the composite films reached at least 94.0%. The antibacterial experiments revealed that PS@PDA/DEF/Ag/PVA-4 wt% exhibited inhibition zone diameters of 3.8 ± 0.3 mm and 3.2 ± 0.3 mm against E. coli O157:H7 and S. aureus. Furthermore, the multifunctional films significantly prevented milk photooxidation for 3 days, jujubes brownish and strawberries decay for 7 days, demonstrating their effectiveness in antibacterial and UV-blocking food packaging.