Green fabrication of transparent Copper(II)-imidazolate metal–organic framework/cellulose nanocomposite films for antibacterial and UV-shielding applications

The combination of two or more seemingly different features into a unique composite is an exciting direction for the preparation of novel versatile materials. Here, we report a facile and green strategy to fabricate transparent multifunctional cellulose-based film material. With carboxymethylated cellulose hydrogel as supporting medium and carboxyl groups as reactive sites, a type of antibacterial, biodegradable and UV-blocking nanocomposite films were fabricated by in situ synthesis of copper(II)-imidazolate metal–organic framework (Cu-MOF). The results show that the nanocomposite films possessed remarkable UV-blocking capability through the whole UV region meanwhile retaining high transmittance. Due to the weak photocatalytic effect of Cu-MOF, the nanocomposite films exhibit high photostability even after continuous UV irradiation (365 nm) for 12 h while maintaining their good mechanical strength. Quite encouragingly, Cu-MOF endowed the film with desirable antibacterial ability, and the antibacterial mechanism could be explained by the release of metal ions and ligands from Cu-MOF. Moreover, the incorporation of Cu-MOF can enhance the mechanical strength of the nanocomposite films. Therefore, the nanocomposite films have great potential for UV protection and transparent antimicrobial packaging applications. Graphical abstract