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

Abstract

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 H₂O, 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.