Pea-like inspired design: Lignin nanospheres-mediated PVA film with high strength, low water evaporation permeability, strong UV resistance and anti-oxidation properties for extending food freshness

The excessive utilization of petroleum-based plastic products has inflicted significant harm upon the ecological and health problems, compelling individuals to continually seek renewable and biodegradable polymer materials as alternatives. Drawing inspiration from the structure of a natural pea pod, a unique interlocking packaging material based on a pea-like structure is obtained via green electrospinning and mild glutaraldehyde (GA) cross-linking method. Herein, polyvinyl alcohol (PVA) serves as a green protective layer encompassing the active lignin nanospheres (LNP) pod, forming a packaging film that prevents LNP migration. The LNP within the fibers can effectively shorten the fiber spacing, and when exposed to the GA vapor, they promote the bonding between neighboring fibers to form a tight interlock structure. Benefiting from the interlocking pea-like structure, the film exhibits excellent tensile strength (3.53 ± 0.02 MPa), wetting strength (1.92 ± 0.05 MPa), and outstanding water vapor barrier properties (3.27 ± 0.3 10−10 gm−1 s−1 Pa−1). Furthermore, the inclusion of LNP endows exceptional water resistance, UV-blocking capabilities, antibacterial and antioxidant properties, which can effectively prolong the storage life of perishable fruits. This eco-logical sustainable design holds tremendous potential in mitigating the burden on the environment, thus making a novel avenue for exploring alternatives to petroleum-derived plastics.