Highly transparent, degradable, and robust bioplastic film for smart packaging

Abstract

The incorporation of smart packaging technology with versatile bio-based materials offers a promising strategy in the realms of food safety and environmental sustainability. Here, we report a novel dual-network, microplastic-free sodium alginate-cellulose fiber paper (SA-CFP) composite film, fabricated through evaporation-induced self-assembly, for intelligent food packaging. Due to the tightly interconnected three-dimensional network formed by the combination of sodium alginate polysaccharide and the cellulose fiber skeleton, the SA-CFP film exhibits high transparency (89.6 %) and excellent mechanical properties (43 MPa), with a tensile strength more than 2.5 times that of pure SA film (16.8 MPa). We further incorporated lanthanide ions were into the SA-CFP film, imparting excellent wet strength (over 18 ± 2.4 MPa) and tunable fluorescence properties. The seaweed-based fluorescent films rapidly respond to biogenic amines, making them suitable as smart tags in the food packaging field. Importantly, the film is fully biodegradable in three months. We report a dual-network seaweed-based plastic film with enhanced comprehensive performance and broadened seaweed's potential for applications as packing materials with lower environmental effects.