A silver nanoparticles-polylactic acid microspheres/polylactic acid-thermoplastic polyurethane nanofibers hierarchical antibacterial film

Silver nanoparticles (AgNPs) are commonly incorporated in food packaging to enhance the shelf life of fruits and vegetables. In this work, three microstructures (spherical, hematocyte-like, and pie micromorphology) of AgNPs-polylactic acid (PLA) materials were fabricated on electrospun PLA-thermoplastic polyurethane (TPU) nanofiber film by electrospraying to reduce the safety risks and the cost of food packaging materials brought by AgNPs. Among them, the spherical AgNPs-PLA microsphere/PLA-thermoplastic polyurethane (TPU) hierarchical antibacterial film had good mechanical properties, a low AgNPs content of 0.6 wt%, the highest water contact angle of 140.1°, the highest bacteriostatic rate of 99% ± 1%, and the least bacterial adhesion. The test of this composite film in strawberry packaging successfully extended the shelf life to over 7 days. The hierarchical PLA material shows promising prospects in food packaging, and the preparation method may be a potential candidate for reducing the amount of antimicrobial agent required in antibacterial materials.