Novel PDI-C8/paraffin fluorescent materials with phase-change modulated luminescence for enhanced anti-counterfeiting security feature

Research on fluorescent composites based on phase change materials is currently a hot topic. In this study, we reported the synthesis of N,N’-bis(1-octylheptadecyl)-3,4,9,10-perylenetetracarboxydiimide (PDI-C8) from perylene-3,4,9,10-tetracarboxylic dianhydride (PDI) and heptadecyl-9-amine. Two types of PDI-C8 paraffin fluorescent materials were developed: PDI-C8/paraffin composites and PDI-C8 paraffin emulsion via the Phase Inversion Composition (PIC) method. The structure, composition, and fluorescence properties of PDI-C8 were studied using NMR, MS, FT-IR, UV and FL, respectively. The photothermal conversion performance of the PDI-C8/paraffin composites was investigated. Results showed improved photothermal conversion with increased PDI-C8 contents, suggesting potential applications in solar thermal energy utilization and storage. The two fluorescent materials were characterized using DSC and FL. The photoluminescence phenomena of PDI-C8 paraffin fluorescent materials with different PDI-C8 contents all exhibit temperature-controlled characteristics. Based on the properties, a fluorescent thermometric paper was developed. Moreover, the utility of the two fluorescent materials extends to fields like anti-counterfeiting identification and encrypted writing.