Organic thin-film fluorescent sensors for vapor with high sensitivity, rapid response, and no pollution to analytes have received widespread attention. However, the development of vapor sensors is very slow. The difficulty lies in most fluorescent materials cannot luminesce in solid state because of ACQ (aggregate concentration quenching) effect. Previous works have usually focused on the design and synthesis of new materials to avoid ACQ effect. Whereas, if existing ACQ materials can be utilized, it will greatly expand the selection range of fluorescent materials used in vapor sensors. In this study, a high-performance vapor sensor utilizing ACQ fluorescent material was successfully prepared based on doping/breath figure method. Firstly, the fluorescence emission of ACQ molecule in solid state was realized by doping with polymer. Then porous sensing film was fabricated via breath figure method (BFs) with large surface-to-volume ratio. Finally, the vapor sensing of ACQ molecule was realized. Herein, the molecule BOR−CHO was selected as ACQ probe doping with polystyrene to get good solid-state luminescence. Then high-quality porous sensing film was obtained by optimizing the BFs parameters. Such a film showed a quick fluorescence quenching response to MPEA (simulant of methamphetamine) gas within 20 s with a detection limit of 1.58 ppm. Our results identify a simple strategy to get enhanced optical intensity of BOR−CHO and achieve superior sensing performance towards MPEA. Most importantly, these findings provide a low-cost method for the facile realization of high surface-to-volume ratio fluorescent sensors for vapor analytes via using ACQ materials, with great flexibility and expandability.
Lin Wang,Jun Wang,Lei Yang,Yexin Ding,Yixiao Xie,Fangming Wang,Lizhuang Chen,Weili Li,Hui Yan
In this research, a novel type of waterborne fluorescent nanofiber membranes (WNFM) based on fluorescent acrylic latex (FAL) has been developed by electrospinning method using environment-friendly water as the spinning solvent. FALs are synthesized by doping Rhodamine B (Rh B) into acrylate monomers through emulsion polymerization, and then polyvinyl alcohol (PVA) is added to fabricate a series of WNFM via electrospinning process. As the hydrophilic emulsifier sodium dodecyl sulfate enriches on the surface of the latex, a portion of Rh B can be adsorbed onto the surface of FAL and form an electrical double layer to prevent its aggregation, which accounts for the enhancement in fluorescence of FALs. The relationships between the preparation conditions, morphology and properties of WNFM have been studied with a combination of techniques including fluorometry and microscopies. The developed waterborne fluorescent nanofiber membranes demonstrate a good water-resistant property with a linear response of photoluminescence intensity to temperature for many cycles. The study points a new direction to develop the nanofiber membrane using environment-friendly water as a spinning solvent in electrospinning and realize its fluorescent functionalization.
Ming Hu,Feng-Ying Ye,Wei Yu,Kang Sheng,Weizhou Wang,Yan-Song Zheng
Graphical New TPE derivatives bearing p -AP groups : Among 5 kinds of crystals of TPE derivative, it is found for the first time that strong intermolecular ArH-pi interactions cause ACQ effect while weak ArH-pi interactions induce AIE phenomenon. The interactions also arouse photochromism, photodeformation and even the first forward rolling movement of crystal by UV light irradiation, providing promising materials in multimode anti-counterfeiting, photo-actuator and light-driven micro-vehicle. Aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) are two classes of opposite luminescence phenomena. It is almost impossible to show both AIE and ACQ effect simultaneously by the same molecule. However, here we report that a simple TPE derivative TAP-TPE grows into both AIE crystals and ACQ ones. It is found that equatorial, contact distance-longer and weak ArH-π interactions exist in AIE crystals while vertical, contact distance-shorter and strong ArH-π interactions appear in ACQ crystals. Theoretical calculation of electron density on the interaction atoms unveils that ACQ crystals have much larger change in electron density than AIE ones, suggesting that the intermolecular electron transfer aroused by the strong ArH-π hydrogen bonds leads to ACQ phenomenon. This result provides a new insight into the emission mechanism in aggregation state. Interestingly, due to the ArH-pi interactions difference, only one of five kinds of crystals shows rapid photochromism, and can act as multimode anti-counterfeiting materials. Very exceptionally, for the first time we find that the photochromic micrometric rod-like crystal even makes forward rolling movement as it repeatedly bends and straightens by responding to on and off of the ultraviolet light irradiation, displaying potential for photo-actuator and light-driven micro-vehicle.
危险品化学品经营许可证（带存储）