Multi-stimuli-responsive phase change hydrogels with dynamic fluorescence chromism based on AIE hydrophobic carbon dots for advanced encryption

Stimuli-responsive fluorescent hydrogels, owing to their tunable optical property and unique smart response characteristics, have significant potential in encryption applications and information security. However, most current systems are limited to single-stimulus responsiveness and lack the capability for programmable information erasure or multi-modal dynamic synergy. Hence, we propose a multi-stimuli-responsive phase-change hydrogel incorporating aggregation-induced emission hydrophobic carbon dots (AIE-HCDs) and polyethylene glycol (PEG)-cellulose network, demonstrating dynamic fluorescence chromism under various external triggers. The hydrogel exhibits solvent-exchange-triggered fluorescence color changes from blue to red, enabled by the concentration modulation of AIE-HCDs through the exchange between PEG and water. Additionally, the temperature-induced phase transition of PEG from crystalline to molten state modulates the aggregation and dispersion of AIE-HCDs, thereby enabling dynamic fluorescence color changes. The phase transition further confers excellent shape-memory behavior and adjustable mechanical properties, with the tensile modulus varying from 6.28 MPa in the molten state to 36.23 MPa in the crystalline state, while maintaining high transparency (∼8% in the molten state). By utilizing microcontact printing and the multi-stimulus response, an encryption platform enables information to be hidden, selectively read under sequential stimuli (thermal, UV, and solvent), and completely erased upon demand. This strategy demonstrates significant potential for advancing high-level information encryption and anti-counterfeiting technologies. The alternative text for this image may have been generated using AI.