Dual host–guest interaction-mediated photoswitchable fluorescent supramolecular polymers for anti-counterfeiting and encryption

Abstract

Supramolecular photoswitchable polymers are widely considered for potential applications in the development of anti-counterfeiting labels and information encryption owing to their advantages of easy functionalization, simple preparation, high brightness, and excellent photoswitchable characteristics. In this study, we describe photoswitchable fluorescent supramolecular polymers (PFSPs) prepared through two independent host–guest interactions (adamantane and β-cyclodextrin, cyanogroup and pillar[5]arene). Based on the fluorescence resonance energy transfer (FRET) principle, AIE-based dyes (NC-DSA-CN) with green fluorescence emission and spiropyran-linked β-cyclodextrin (CDSP) were utilized to create light-induced FRET systems. NC-DSA-CN was fixed through supramolecular interaction to prevent intramolecular rotation, resulting in excellent fluorescence properties in both the solution and the solid state. In this system, when the donor/acceptor ratio was up to 150 : 1, the FRET efficiency was 89.2%, and PFSPs showed superior photoswitchable performance, including fast photo-responsibility and prominent photo-reversibility. Thanks to their AIE and photoswitchable properties, PFSPs were successfully applied in the construction of information encryption and anti-counterfeiting systems.