Layer-by-Layer Assembly of Polysaccharide Films with Self-Healing and Antifogging Properties for Food Packaging Applications

Self-healable, transparent, and antifogging polysaccharide films composed of acrylamide-modified chitosan (AMCS) and alginate aldehyde (ADA) were fabricated via layer-by-layer (LBL) assembly. The Schiff base linkage formed between amino groups of AMCS and aldehyde groups of ADA was used to construct the films. Fourier transform infrared spectroscopy and X-ray photoelectron spectra revealed that the films were cross-linked through Schiff base bonds. Ultraviolet–visible spectroscopy and field emission scanning electron microscope characterizations demonstrated that the films exhibited linear growth during the LBL process. The films showed a repetitive self-healing property, and the repeated damage-healing of the films was thickness-dependent. The films can heal the scratches that penetrated to the underlying substrates. Besides the excellent self-healing property, the films showed an antifogging property due to the hydrophilic nature of the two polysaccharides. The antifogging ability of the film was thickness-dependent. Also, the films could regain their transmittance and fog-resistant property after mechanical abrasion due to their self-healing capability. These self-healable and fog-resistant polymeric films have potential applications in food packaging.