Plasma‐Assisted Electrospinning of PLA / PVA /ε‐Polylysine Bilayer Antibacterial Films for Active Food Packaging

With the increasing awareness of environmental protection and growing emphasis on food safety and quality, the development of environmentally friendly antibacterial packaging materials has become a mainstream trend. Polylactic acid (PLA), as a degradable material, meets the needs of green packaging development, but pure PLA lacks antibacterial properties, which severely limits its application in perishable food packaging. This study aims to prepare PLA‐based composite films with both antibacterial properties and excellent comprehensive performance through functional coating modification to break through the application limitations of pure PLA materials. By employing electrospinning technology, a mixture of polyvinyl alcohol (PVA) and ε‐polylysine (ε‐PL) was spun onto a plasma‐treated PLA substrate to successfully fabricate a bilayer antibacterial film, and the effects of ε‐PL concentrations (0%, 5%, 10%, 20%) on the properties of the PLA‐based composite films were investigated. The results demonstrate that plasma treatment can effectively enhance the adhesion between the electrospun coating and the PLA substrate while eliminating interfacial gaps. For the PLA/PVA/ε‐PL composite films, as the ε‐PL concentration increases, the oxygen barrier property improves, with the oxygen transmission rate (OTR) decreasing gradually from 141.77 cm 3 m −2 day −1 0.1 MPa −1 (0%‐ε‐PL) to 118.55 cm 3 m −2 day −1 0.1 MPa −1 (20%‐ε‐PL), while the tensile strength, contact angle, and thermal stability gradually decreased. Whereas in terms of water vapor permeability (WVP), the WVP of the composite film is higher than that of pure PLA film and exhibits a trend of first decreasing and then increasing with the increase of ε‐PL concentration. Notably, antibacterial tests indicate that the PLA film combined with the ε‐PL‐based electrospun coating possesses strong antibacterial activity, which enhances with the increase of ε‐PL concentration, with the optimal antibacterial performance achieved at 20% ε‐PL concentration—exhibiting an antibacterial rate of 94.7% against Escherichia coli ( E. coli ) and 80.7% against Staphylococcus aureus ( S. aureus ). Furthermore, this composite film integrates degradability with excellent antibacterial and barrier properties, boasting broad application prospects in the packaging of perishable foods for extending food shelf life and reducing food safety risks, thereby providing technical support for the environmental and functional upgrading of food packaging.