Development of sustainable active smart Fe-CIT/PVA nanocomposite-based films for monitoring shrimp freshness

A new dual-functional Fe-CIT complex nanocrystal with good antimicrobial effect and colorimetric ammonia-sensitivity was synthesized and then introduced into polyvinyl acetate (PVA) film-forming matrix to construct active smart packaging films with excellent performances. Results revealed that the Fe-CIT complex could form robust hydrogen bonding interaction with PVA film matrix, resulting in an ultra-high tensile ductility (372.81 %). The fabricated Fe-CIT/PVA film also exhibited a significantly improved hydrophobicity (84.3°), UV-blocking efficacy (100 %), and oxygen/water barrier capacity. Furthermore, the Fe-CIT/PVA film possessed outstanding long-term color stability, biocompatibility, antimicrobial activity, and colorimetric ammonia-sensitivity. Application trials confirmed that the Fe-CIT/PVA smart film was capable of effectively monitoring the freshness of shrimp during storage at 4 °C and 25 °C. This work demonstrates that dual-functional Fe-based complex (Fe-CIT) serves as a stable and effective active element, showing promising commercial potential in terms of cost-effectiveness and scalability for the development of advanced smart active packaging materials.