Aggregation‐Induced Emission‐Active Gels: Fabrications, Functions, and Applications

Abstract

Chromophores that exhibit aggregation‐induced emission (i.e., aggregation‐induced emission luminogens [AIEgens]) emit intense fluorescence in their aggregated states, but show negligible emission as discrete molecular species in solution due to the changes in restriction and freedom of intramolecular motions. As solvent‐swollen quasi‐solids with both a compact phase and a free space, gels enable manipulation of intramolecular motions. Thus, AIE‐active gels have attracted significant interest owing to their various distinctive properties and promising application potential. Herein, a comprehensive overview of AIE‐active gels is provided. The fabrication strategies employed are detailed, and the applications of AIEgens are summarized. In addition, the gel functions arising from the AIE moieties are revealed, along with their structure–property relationships. Furthermore, the applications of AIE‐active gels in diverse areas are illustrated. Finally, ongoing challenges and potential means to address them are discussed, along with future perspectives on AIE‐active gels, with the overall aim of inspiring research on novel materials and ideas.

Fluorescent supramolecular polymers of barbiturate dyes with thiophene-cored twisted π-systems

“…In the above context, even classical supramolecular units are attractive to design aggregation-induced emission luminogens (AIEgens) that can organize into well-defined one-dimensional structures. 6 As one such supramolecular unit, we are interested in barbiturate, 7 which have long been known to exhibit crystalline polymorph by the formation of infinite tape-like hydrogen-bonded motifs ( Fig. 1a , right).…”

Developing Novel Fabrication and Optimisation Strategies on Aggregation-Induced Emission Nanoprobe/Polyvinyl Alcohol Hydrogels for Bio-Applications

“…The recent discovery of aggregation-induced emission fluorogens (AIEgens) with high emission efficacy in the aggregated state, unique photostability, noticeable diversity of molecular structures, and acceptable sensitivity have demonstrated new opportunities to overcome the major drawback [ 25 ]. AIEgens have been widely used for the preparation of fluorescent hydrogels [ 26 , 27 ]. Indeed, AIEgens exhibit enhanced fluorescent properties within a confined polymer network due to the restriction of their intramolecular rotation occurring via chemical or physical interactions.…”

Solvent- and Light-Sensitive AIEE-Active Azo Dye: From Spherical to 1D and 2D Assemblies

“…The intramolecularly strong B-N interaction disrupts the molecular structural changes around the azo group, which is mainly responsible for the high fluorescence efficiency. Yoon et al examined the aggregation-induced emission enhancement (AIEE [47][48][49][50][51][52]) property of o-phenylazonaphthol (o-PAN)-based chromophores [53]. The planarization associated with strong intramolecular hydrogen bonding and the restriction of intramolecular rotation in the hydrazone tautomer form are likely responsible for the enhanced fluorescence.…”