Ionogels with Excitation Wavelength Dependent Emission and Dynamic Light‐Tracking for Potential Extreme Rescues

Abstract Photoluminescent materials with excitation wavelength dependent (Ex‐De) emission are promising for the next generation of photo‐response materials. To advance the Ex‐De performance beyond conventional systems, new design paradigms are needed. Here Ex‐De ionogels are developed by introducing ionic liquids as both fluorophores and solvents. The ionogels are formed by the copolymerization and cross‐linking of acrylic acid (AA) and 2,2,3,4,4,4‐hexafluorobutyl acrylate (HFBA) in imidazolium ionic liquid. The 3D ionogel network tethers imidazolium cations to the polymer backbones, imparting multi‐color Ex‐De characteristics triggered by imidazolium‐conjugated aggregates and polymer clusterization, while also offering stabilization in various conditions. The ionogels exhibit Ex‐De behaviors with the fluorescence emission from blue at 400 nm to yellow at 575 nm when irradiated with different excitation wavelengths from 300 to 500 nm. The Ex‐De emission remains after 30 days under both high relative humidity (90% RH) or immersion in organic solvents. Vibrant luminescence is also observed at elevated temperature (100 °C) and cryogenic temperature (−20 °C), or under twisting, bending and stretching to 500% of strain. The stability of ionogels in harsh environments provides opportunities for applications in dynamic camouflage, multiple information encryption, and potential extreme rescues. This work presents a new design concept for next‐generation Ex‐De materials.