RESUMO
Forgery and low-quality products pose a danger to society. Therefore, there are increasing demands for the production of easy-to-recognize and difficult-to-copy anticounterfeiting materials. Products with smart photochromic and fluorescence properties can change colour and emission spectra responding to a light source. In this context, we devised a straightforward preparation of a luminescent polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) nanocomposite to function as a transparent labelling film. The lanthanide-doped aluminate (LdA) was prepared in the nanoparticle form to indicate diameters of 35-115 nm. Different ratios of the LdA were physically dispersed in the PVA/CMC nanocomposite label film to provide photochromic, ultraviolet protection, antimicrobial activity, and hydrophobic properties. Fluorescence peaks were detected at 365 and 519 nm to indicate a colour change to green. As a result of increasing the phosphor ratio, improved superhydrophobic activity was achieved as the contact angle was increased from 126.1° to 146.0° without affecting the film's original physical and mechanical properties. Both ultraviolet (UV) light protection and antibacterial activity were also investigated. The films showed a quick and reversible photochromic response without fatigue. The current strategy reported the development of a photochromic smart label that is transparent, cost effective, and flexible. As a result, numerous anticounterfeiting products can benefit from the current label for a better market. LdA-loaded PVA/CMC films demonstrated antibacterial activity between poor, good, very good, and outstanding as the percentage of LdA in the film matrix increased. The current film can be applied as a transparent photochromic security barcode for anticounterfeiting applications and smart packaging.