Enhancing Antimicrobial and Antioxidant Properties of Chitosan-Based Films with 1-Methylimidazolium-Chitosan

The design and the synthesis of functional films with enhanced functionality represent a significant step forward in sustainable material development due to their potential applications. In this study, a novel chitosan derivative (CS-MeIm) was synthetized by chemically modifying chitosan (CS) structure with 1-methyl-1H-imidazole (MeIm), a heterocyclic compound known for its biological properties. This functionalization not only enhances the intrinsic capabilities of CS but also provides a strategic platform for advanced material engineering. The modified compound, CS-MeIm, was incorporated at 10 wt% into films based on CS matrix, which was also reinforced with 1 or 5 wt% of chitin nanowhiskers (ChNw), to improve their functionality for its potential applications. The fabrication process was optimized to ensure the homogeneity and the structural integrity of the films, which were extensively evaluated to study their thermal stability, mechanical integrity, and bioactivity. The incorporation of the imidazole ring into the CS backbone provided a marked enhancement in antioxidant capacity from 3 to 15 μmol Trolox/gram of film; and excellent antimicrobial activity against common microbes, particularly against E. coli with an efficacy of 99.999%. The findings reveal that this chemical modification not only raises the intrinsic properties of CS but also introduces a versatile platform for creating biodegradable films with high functionality.