Versatile and robust transparent polymer film with preprogrammed diffusion and bidirectional irreversible...

The materials currently available for information encryption often suffer from low transparency, poor mechanical strength, and a reliance on single decryption conditions, which limits their security and hence application potential. To address these challenges, we developed a transparent, mechanically robust polymer film inspired by the camouflage and communication strategies of the glass squid. In this film, 2,5-dihydroxyterephthalic acid (DHTA) and zinc acetate dihydrate are integrated into a crosslinked polyvinyl alcohol-glutaraldehyde (PVA-GA) matrix to achieve bidirectional irreversible fluorescence and sequential decryption. The material exhibits high transparency (>89 %) and impressive tensile strength (60 MPa), and its fluorescence responses can be tuned with UV light, alkaline conditions, and high-temperature ethanol solutions. Based on preprogrammed diffusion rates, customizable time-based decryption can be achieved with the film, advancing multilevel encryption techniques. These findings demonstrate that this film represents a promising platform for secure information encryption and anticounterfeiting applications.