A multifunctional cardanol-based room-temperature phosphorescent material with multi-stimulus-responsive shape-memory for anti-counterfeiting and encryption.

The development of room temperature phosphorescence (RTP) in multi-stimulus-responsive shape memory materials for applications in information encryption and anti-counterfeiting presents a significant challenge. Here, we introduce a cardanol-based polymer system containing N-coordinated bicyclic boronic esters, which exhibit stable, long-lived RTP and respond to multiple stimuli, including heat, ultraviolet (UV), and infrared (IR) light. This is achieved through a well-designed copolymer structure that integrates rigidity and dynamic covalent networks by adjusting the N-coordination with the bicyclic boronic ester linkage, and the material can be engineered for self-healing and recyclability. The resulting cardanol-based RTP demonstrates ultralong afterglow emissions lasting up to 12 s under ambient conditions. Remarkably, it retains conspicuous RTP even immersed in HO, HCl and NaOH for four weeks, thanks to its 3D covalent network structure providing exceptional water and chemical resistance. Furthermore, its UV-responsive properties enable the cardanol-based RTP to function as a rewritable film for light printing. Leveraging the shape memory and adjustable phosphorescence performance, we developed a promising programmable 2D/3D anti-counterfeiting security system based on this cardanol-based RTP. This system combines phosphorescence and shape memory behaviors, advancing the development of multi-stimulus-responsive RTP systems based on cardanol, and offering promising applications in secure information storage and anti-counterfeiting technologies.