Evaporation-coded fluorescent gradients in supramolecular gels displaying aggregation-induced emission: A dynamic route to encryption and anti-counterfeiting.

Abstract

Supramolecular gels have been widely explored as functional materials; however, their performance often degrades upon solvent evaporation. Although many strategies seek to mitigate this instability, few have leveraged solvent loss as a functional driver. Herein, we present an aggregation-induced emission (AIE)-active supramolecular gel that exploits solvent evaporation for dynamic information encryption and anti-counterfeiting. In this multicomponent co-assembly, a phenylalanine-functionalized 1,3,5-benzenetricarboxamide derivative (C₃-Phe), sodium hyaluronate (HA), and Al³⁺ ions together immobilize the AIE luminogen 4,4'-(1,2-diphenylethene-1,2-diyl)dibenzoic acid (TPE-CA), enhancing its quantum yield from 1.91 % to 62.43 %. The introduction of fluorescent dyes 4,7-di(2-thienyl)-2,1,3-benzothiadiazole (DBT) and rhodamine B (RhB) further establishes a cascade Förster resonance energy transfer (FRET) platform to enable tunable multicolor emission. The controlled evaporation of water drives time-dependent fluorescence chromatic shifts and quenching, which are fully reversible upon water replenishment. This evaporation-coded reversible fluorescence behavior underpins a 4D encryption and anti-counterfeiting platform that features multistage authentication and self-erasing information, thereby offering a new paradigm for adaptive smart materials.