Constrained photoinduced electron transfer (PET) luminescence enabling dual modal microenvironment probing and information encryption

Abstract

The rational design of luminescent materials requires precise control over emission mechanisms; however, the complex non-covalent interactions (NCI) in polymeric systems, including segment motions, chain entanglement, crystallization, and phase separation in polymers, present significant challenges. Here, we employ a maleimide-substituted tetraphenylethylene derivative (TPEDMI) exhibiting photoinduced electron transfer (PET) characteristics, blended with tunable styrene–butadiene polymers (PB, PS, SBR, SBS) and functional derivatives (SBS–Fu, SBS–OH). Using experimental and computational methods (materials studio (MS) and density functional theory (DFT)), this work elucidates how electron donor/acceptor capacity and microenvironmental stiffness within TPEDMI&polymer blends influence constrained PET emission, thereby contributing to advanced solid-state polymer detection. Crucially, this system fundamentally differs from previous strategies that activated TPE/TPEMI emission through stiffness-restricted intramolecular motion (RIM) in blends or through covalent/supramolecular PET blocking. Furthermore, TPEDMI's capacity to engage in both Diels–Alder (D–A) and thiol–maleimide click reactions allows for a direct comparison of their dynamic behaviors. This not only demonstrates reaction-modulated PET blocking but also delivers critical insight into NCI-driven systems, offering valuable guidelines for designing new functional materials. More importantly, we demonstrate a novel mechanism for color change observed in the blend SBS–Fu&TPEDMI_10%. By utilizing these mechanisms, we successfully achieved applications in information encryption. This work provides fundamental insights into NCI-governed luminescence and design principles for stimulus-responsive materials.