ORCID Profile
0000-0003-1890-3606
Current Organisations
Donghua University Songjiang Campus
,
Hong Kong University of Science and Technology
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Publisher: Wiley
Date: 28-02-2019
Publisher: Wiley
Date: 07-12-2017
Publisher: Wiley
Date: 14-02-2019
Publisher: Wiley
Date: 23-04-2018
Abstract: A facile and efficient approach is demonstrated to visualize the polymerization in situ. A group of tetraphenylethylene (TPE)‐containing dithiocarbamates were synthesized and screened as agents for reversible addition fragmentation chain transfer (RAFT) polymerizations. The spatial‐temporal control characteristics of photochemistry enabled the RAFT polymerizations to be ON and OFF on demand under alternating visible light irradiation. The emission of TPE is sensitive to the local viscosity change owing to its aggregation‐induced emission characteristic. Quantitative information could be easily acquired by the naked eye without destroying the reaction system. Furthermore, the versatility of such a technique was well demonstrated by 12 different polymerization systems. The present approach thus demonstrated a powerful platform for understanding the controlled living radical polymerization process.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9QM00332K
Abstract: A tunable CPL response is achieved through regulating the aggregated structures of AIEgens in solution and solid states. Interestingly, DPCE-ECh exhibits a smectic C* phase with a high dissymmetry factor ( g CD = −0.20 and g lum = +0.38).
Publisher: Wiley
Date: 28-02-2019
Abstract: The development of molecular machines requires new building blocks which are easy to characterize and visualize to realize a complexity comparable to their natural counterparts such as biological enzymes. Furthermore, with the desire to build functional nanobots capable of navigating living organisms, it is necessary that the building blocks show mobility even in the solid state. Herein we report a system which is emissive in the amorphous state but is non-fluorescent in the crystalline state due to the formation of extensive π-π interactions. This dual nature could be exploited for easy visualization of its solid-state molecular rearrangement. The emission of the amorphous film was quenched as the molecules spontaneously formed π-π interactions even in the solid state. Scratching the non-emissive film destroyed the interactions and restored the emission of the film. The emission quickly disappeared with an average lifetime of 20 s as the compound reformed the π-network even at room temperature.
Publisher: Wiley
Date: 16-10-2017
Abstract: Building humidity sensors possessing the features of erse-configuration compatibility, and capability of measurement of spatial and temporal humidity gradients is of great interest for highly integrated electronics and wearable monitoring systems. Herein, a visual sensing approach based on fluorescent imaging is presented, by assembling aggregation-induced-emission (AIE)-active molecular rotors into a moisture-captured network the resulting AIE humidity sensors are compatible with erse applications, having tunable geometries and desirable architectures. The invisible information of relative humidity (RH) is transformed into different fluorescence colors that enable direct observation by the naked eyes based on the twisted intramolecular charge-transfer effect of the AIE-active molecular rotors. The resulting AIE humidity sensors show excellent performance in terms of good sensitivity, precise quantitative measurement, high spatial-temporal resolution, and fast response/recovery time. Their multiscale applications, such as regional environmental RH detection, internal humidity mapping, and sensitive human-body humidity sensing are demonstrated. The proposed humidity visualization strategy may provide a new insight to develop humidity sensors for various applications.
Publisher: American Chemical Society (ACS)
Date: 04-12-2020
Publisher: American Chemical Society (ACS)
Date: 11-12-2018
Abstract: Many highly ordered structures with smart functions are generated by self-assembly with stimuli responsiveness. Despite that electron microscopes enable us to directly observe the end products, it is hard to visualize the initial step and the kinetic stimuli-responsive behavior of self-assembly. Here, we report the design and synthesis of stereogenic hiphiles, namely, ( Z)-TPE-OEG and ( E)-TPE-OEG, with aggregation-induced emission (AIE) characteristics from the hydrophobic tetraphenylethene core and thermoresponsive behavior from the hydrophilic oligoethylene glycol monomethyl ether chain. The two isomers can be easily isolated by high-performance liquid chromatography and characterized by 2D NMR spectroscopy. While ( Z)-TPE-OEG self-assembles into vesicles, its ( E)-cousin forms micelles in water. The initial step of their self-assembly processes can be visualized based on AIE characteristics, with a sensitivity much higher than the method based on transmittance measurement. The entrapment and release capabilities of the ( Z)-stereogenic hiphile are demonstrated by employing pyrene as a guest. The thermoresponsive behavior of the ( Z)- hiphile results in its continuous phase transition from microscopic self-assembly to macroscopic aggregation, which is successfully visualized in situ by confocal laser scanning microscopy accompanied by the AIE technique. Such a kinetic process shows different stages according to the microscopic visualization, and these stages have never been monitored through roughly observing the appearance of precipitates. It is anticipated that this study can deepen the understanding of the self-assembly processes for better monitoring and controlling them in different systems.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SC04239C
Abstract: A polymorphic AIEgen is capable of selective growth in amorphous and crystalline polymer phases with distinct color for microstructure visualization.
Publisher: American Chemical Society (ACS)
Date: 07-01-2020
Abstract: Molecules have limited mobility in the solid state because of the strong intermolecular interactions, and therefore, applications based on solid-state molecular motions are seldom explored. Herein, by manipulating the solid-state intramolecular motion of tetraphenylethylene (TPE) in a crystallizing polymer matrix, controlled fluorescent patterns with information storage and encoding functionality are developed. The intramolecular mobility of TPE can not only affect the fluorescence intensity but also determine the photocyclization activity, which can be tuned by surrounding polymer rigidity. The soft amorphous region in the semicrystalline polymer facilitates the intramolecular motion to achieve weak blue emission and high photocyclization activity, whereas the rigid crystalline phase restricts the intramolecular motion to give intense blue emission and low photoreactivity. Meanwhile, in the process of crystallization, the dynamic movement of the polymer chain in the crystal growth boundary layer further accelerates the intramolecular motions of TPE, allowing enhanced photoreactivity across crystalline and amorphous regions. The motion-dominated fluorescence allows TPE as a smart molecular robot to generate desired fluorescent patterns triggered by polymer crystallization. Our findings provide a correlation between microscopic molecular motions and macroscopic optical signals.
Publisher: American Chemical Society (ACS)
Date: 13-05-2020
Location: United States of America
No related grants have been discovered for Yanhua Cheng.