Aggregation Induced Emission (AIE)‐Active Poly(acrylates) for Electrofluorochromic Detection of Nitroaromatic Compounds

Abstract

Two aggregation induced emission (AIE)-active poly(acrylates) bearing triphenylvinyl-functionalized phenylcarbazole and triphenylamine pendants, respectively, were synthesized. Their fluorescence response to nitroaromatics and electrofluorochromic (EFC) properties were studied, whereby both the presence of nitroaromatics and applied voltages led to fluorescence quenching. In a very first attempt to perform EFC detection of nitroaromatics, it was surprisingly found that after initial fluorescence quenching, the presence of nitroaromatics unexpectedly turned on fluorescence at high applied voltages (> + 1.0 V), demonstrating a promising approach for the EFC detection of nitroaromatic explosives.

Aggregation-Induced Emission-Active Nanostructures: Beyond Biomedical Applications

“…The rapid detection of explosives has always been of paramount importance due to national security, and the development of fluorescent explosive sensors has circumvented the need for time-consuming and costly routine instrumental analysis. Nitroaromatic explosives such as trinitrotoluene and picric acid are commonly detected by AIE-active polymers in the forms of highly emissive nanoaggregate solutions, thin films, or paper probes via photoinduced electron transfer (PET) fluorescence quenching. − Previously, Tang et al prepared AIE-active nanosheets with approximately 7.0 nm thickness by crystallization of a poly­(ε-carprolactone) (PCL) terminated with two TPE moieties ( 15 ), which interestingly led to the TPE moieties pointing out, dangling on the surfaces of the lamellar structures (Figure a1) . The blue-emissive nanosheets were found to selectively sense picric acid among other nitroaromatics via fluorescence quenching with a Stern–Volmer constant of 380,000 L/mol (Figure a2).…”

Stimuli-responsive structure–property switchable polymer materials

“…Through the use of multiple non-covalent binding motifs, these polymers are often capable of exhibiting reversible responsiveness to a myriad of stimuli. [227][228][229] For example, Jiang et al reported a stable supramolecular polymer containing tripodal pillar [5]arene tails. This supramolecular polymer can undergo reversible gel-sol transition via pH, thermal, and force stimuli and demonstrate strong AIE after gelation (Figure 28b).…”

“…Xiong and coworkers employed a novel AIE luminogen to design an organic multi-stimuli responsive fluorescent material. 228,232 Consisting of vinylpyridine motifs on a tetraphenylethene backbone, the AIE luminogen displayed reversible fluorescence under varying force, pH, and temperature stimuli. Due to the supramolecular intermolecular interactions as well as the presence of shrinkable space in the polymer's packing structure, the material can sustain fluorescence emission even under external pressure as high as 11.25 GPa.…”

Recent advances in aggregation-induced emission (AIE)-based chemosensors for the detection of organic small molecules

“…361 More recently, in a follow-up of a previous work on AIE luminogens, 362 Chua and Xu et al synthesized AIE-active polyacrylates ( D21 ) bearing triphenylvinyl-functionalized triphenylamine and phenylcarbazole pendants with green and blue fluorescence, respectively. 52 While the presence of NACs led to fluorescence quenching of D21 due to PET, the application of voltage unexpectedly “turn-on” the fluorescence. The design of TPE-containing amphiphilic block copolymers ( D22 ) was investigated.…”

“…The discovery of AIE phenomena has therefore revolutionized the fundamental concept of photoluminescence properties of materials, and how their high photoluminescent quantum yield (PLQY) in solid and aggregated states may allow them to be exploited in real life applications and state-of-the art technologies. In addition to chemical sensing, AIEgens can be exploited for biomedical applications such as biosensing, bioimaging and theranostics, [36][37][38][39][40][41][42] in optoelectronics for LED, photovoltaics, and electrofluorochrome applications, [43][44][45][46][47][48][49][50][51][52] as well as stimuli-responsive materials. 53 To date, a large number of AIE-based fluorescent probes have been reported, for the detection of a wide range of analytes including metal and inorganic ions, small molecules, macromolecules, enzymes and peptides.…”