Dedicated to Professor Daoben Zhu on the occasion of his 80th birthday The past one hundred years have witnessed the great development of polymer science. The advancement of polymer science is closely related with the development of characterization techniques and methods, from viscometry in molecular weight determination to advanced techniques including differential scanning calorimetry, nuclear magnetic resonance, and scanning electron microscopy. However, these techniques are normally constrained to tedious sample preparation, high costs, harsh experimental conditions, or ex situ characterization. Fluorescence technology has the merits of high sensitivity and direct visualization. Contrary to conventional aggregation-causing quenching fluorophores, those dyes with aggregation-induced emission (AIE) characteristics show high emission efficiency in aggregate states. Based on the restriction of intramolecular motions for AIE properties, the AIE materials are very sensitive to the surrounding microenvironments owing to the twisted propeller-like structures and therefore offer great potential in the study of polymers. The AIE concept has been successfully used in polymer science and provides a deeper understanding on polymer structure and properties. In this review, the applications of AIEgens in polymer science for visualizing polymerization, glass transition, dissolution, crystallization, gelation, self-assembly, phase separation, cracking, and self-healing are exemplified and summarized. Lastly, the challenges and perspectives in the study of polymer science using AIEgens are addressed.
Driven by the urgent demand for novel electrochemiluminescence reagents, a water-soluble polyfluorene derivative, poly [(9,9-bis (3-((N,N-dimethylamino)N-ethy-lammonium) propyl)-2,7-fluorene)-alt-2,7-(9,9-p-divinylbenzene)] dibromide (P-2), was designed and success-fully synthesized. Ultraviolet-visible spectroscopy and fluorescence spectroscopy were used to characterize the formation of P-2, and the results showed that P-2 had strong fluorescence intensity. More importantly, electrochemiluminescence (ECL) of the prepared P-2 was also observed when the applied potential was cycled between 1.0 to 2.8 V at 100 mV·s-1 in phosphate buffered saline buffer solution (pH 8.20). Based on the stable ECL performance, an ECL system for bovine serum albumin (BSA) was constructed. Under the optimal conditions, the enhanced ECL intensity was linearly correlated to the concentration of BSA over the range of 5.0×10-8-1×10-4 g·mL-1 (R=0.9996) with a detection limit of 1.26×10-8 g·mL-1 (n=11). This work not only introduced a substitute for traditional ECL regents, but also proposed a simple ECL system for other analytes.
Background:
Restrained by the aggregation-causing quenching of conventional fluorophores, the design and synthesis of solid-state emissive materials is a persistent pursuit for scientists. The discovery of aggregation-induced emission provides an efficient strategy to prepare solid-state emissive luminogens.
Method:
A multifunctional solid-state emissive material DMBTPE was prepared from tetraphenylethylene from N-methylated barbituric acid through the construction of donor-acceptor structure.
Results:
DMBTPE showed typical aggregation–induced emission characteristic: non–emissive when molecularly dissolved in solution while strongly emissive in aggregated state or as solid. Owing to the strong donor–acceptor interaction, the maximum absorption of DMBTPE shifted to the visible light region. DMBTPE also exhibited reversible mechanochromic fluorescence with emission wavelength change 30–40 nm. DSC and XRD results indicated the transition between amorphous state and crystalline state was accounted for the mechanochromic fluorescence behavior. The microcrystalline rods of DMBTPE grown from hot ethanol solution exhibited good optical wave–guiding effect and the optical loss was as low as 0.018 dB/μm.
Conclusions:
DMBTPE was an efficient solid emitter. Such attributes enable this kind of materials to find wide applications in many areas such as biological imaging and optoelectronic devices.
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