Supramolecular Lock-Shell Layer Nanocapsules Enabling Polyethylene with Long-Term Antifogging Ability

Antifogging packaging is crucial for prolonging the shelf life of products in the fields of food, vegetable, and fruit preservation. To date, obtaining antifogging films with the merits of ease of preparation, facilitation of large-scale industrialization, and outstanding reliability through common thermoplasticization methods like film blowing is challenging. Herein, we develop a facile method to prepare hydrophilic core-shell nanocapsules with a particle size less than 200 nm, which are composed of the inner amphiphilic Span-80 molecules acting as main antifogging units and the outer cross-linked copolymeric networks as supramolecular lock-shell layers and supplementary antifogging units to prevent the rapid migration of Span-80 from the hydrophobic polyethylene (PE) host. Long-term antifogging PE films composed of PE pellets and different contents of the prepared hydrophilic nanocapsules are directly obtained by using the most industrialized film blowing technique. Chemical structure, optical, mechanical, thermal, and antifogging performances of the produced antifogging films are evaluated. The results reveal that the synthesized nanocapsules with the supramolecular lock-shell layer show outstanding storage stability, form stability, hydrophilicity, and thermal stability. PE films with the content of the encapsulated Span-80 nanocapsules of about 1.6 per hundred rate can exhibit excellent hydrophilicity. The practical antifogging effect of the produced nanocapsule-doped PE films reveals that the film can still show remarkable antifogging ability even after experiencing various harsh conditions such as friction, water washing, and long-term storage and that the film can effectively prolong the shelf time of common vegetable and fruit. The strategy of the fabricated antifogging PE films probably opens a new avenue to develop the next generation of long-term antifogging packaging films.