Geometric (Z)- and (E)-isomers play important but different roles in life and material science. The design of new (Z)-/(E)- isomers and study of their properties, behaviors, and interactions are crucially important in molecular engineering. However, difficulties with their separation and structure confirmation limit their structural diversity and functionality in scope. In the work described herein, we successfully synthesized pure isomers of ureidopyrimidinone-functionalized tetraphenylethenes ((Z)-TPE-UPy and (E)-TPE-UPy), featuring both the aggregation-induced emission characteristic of tetraphenylethene and the supramolecular polymerizability of ureidopyrimidinone. Their structures were confirmed by 2D COSY and NOESY NMR spectroscopies. The two isomers show distinct fluorescence in the aggregate state: (Z)-TPE-UPy exhibits green emission, while its (E)-counterpart is blue-emitting. The cavity formed by the two ureidopyrimidinone groups of (Z)-TPE-UPy makes it suitable for Hg detection, and the high-molecular-weight polymers prepared from (E)-TPE-UPy can be used to fabricate highly fluorescent fibers and 2D/3D photopatterns from their chloroform solutions.
Heterocyclic polymers have gained enormous attention for their unique functionalities and wide applications. In contrast with the well-studied polymer systems with five- or six-membered heterocycles, functional polymers with readily openable small-ring heterocycles have rarely been explored due to their large synthetic difficulty. Herein, a facile one-pot multicomponent polymerization to such polymers is developed. A series of functional polymers with multisubstituted and heteroatom-rich azetidine frameworks are efficiently generated at room temperature in high atom economy from handy monomers. The four-membered azetidine rings in the polymer skeletons can be easily transformed into amide and amidine moieties via a fast and efficient acid-mediated ring-opening reaction, producing brand-new polymeric materials with distinctive properties. All the as-prepared azetidine-containing polymers exhibit intrinsic visible luminescence in the solid state under long-wavelength UV irradiation even without conventionally conjugated structures. Such unconventional luminescence is attributed to the clusteroluminogens formed by through-space electronic interactions of heteroatoms and phenyl rings. All the obtained polymers show excellent optical transparency, high and tunable refractive indices, low optical dispersions and good photopatternability, which make them promising materials in various advanced electronic and optoelectronic devices. The ring-opened polymers can also function as a lysosome-specific fluorescent probe in biological imaging.
Polyelectrolytes play an important
role in both natural biological
systems and human society, and their synthesis, functional exploration,
and profound application are thus essential for biomimicry and creating
new materials. In this study, we developed an efficient synthetic
methodology for in situ generation of azonia-containing
polyelectrolytes in a one-pot manner by using readily accessible nonionic
reactant in the presence of commercially available cheap ionic species.
The resulting polyelectrolytes are emissive in the solid state and
can readily form luminescent photopatterns with different colors.
The azonia-containing polyelectrolytes possess extraordinary potency
of reactive oxygen species (ROS) generation, enabling them to impressively
kill methicillin-resistant Staphylococcus aureus (MRSA),
a drug resistant superbug, both in vitro and in vivo.
Polymer dielectrics with excellent processability and high breakdown strength (Eb) enable the development of high‐energy‐density capacitors. Although the improvement of dielectric constant (K) of polymer dielectric has been realized by adding high‐K inorganic fillers with high contents (>10 vol%), this approach faces significant challenges in scalable film processing. Here, the incorporation of ultralow ratios (<1 vol%) of low‐K Cd1−xZnxSe1−ySy nanodots into a ferroelectric polymer is reported. The polymer composites exhibit substantial and concurrent increase in both K and Eb, yielding a discharged energy density of 26.0 J cm−3, outperforming the current dielectric polymers and nanocomposites measured at ≤600 MV m−1. The observed unconventional dielectric enhancement is attributed to the structural changes induced by the nanodot fillers, including transformation of polymer chain conformation and induced interfacial dipoles, which have been confirmed by density function theory calculations. The dielectric model established in this work addresses the limitations of the current volume‐average models on the polymer composites with low filler contents and gives excellent agreement to the experimental results. This work provides a new experimental route to scalable high‐energy‐density polymer dielectrics and also advances the fundamental understanding of the dielectric behavior of polymer nanocomposites at atomistic scales.
We review the fabrication processes and properties of waveguides that have been made from chalcogenide glasses including highly nonlinear waveguides developed for all-optical processing.
The visualization of microphase separation in immiscible polymer blends is of great academic and industrial significance as the phase-separated structures are directly associated with the properties and performances of the blend materials and ultimately influence the corresponding product quality. However, conventional techniques for detecting microphase separation are generally expensive and time-consuming with troublesome and even destructive sample preparation procedures. Complicated and highly material-dependent chemical reactions or interactions are often involved in some characterization approaches. In this work, we demonstrated a simple, fast, and powerful method for high-contrast visualization and differentiation of micrometer-sized phase separation in polymer blends using luminogens with aggregation-induced emission characteristics (AIEgens) as fluorescent probes. This method relies on the sensitive fluorescence response of AIEgens to the change of environmental rigidity and polarity and operates based on the mechanisms of "restriction of intramolecular motions" and "twisted intramolecular charge transfer". The working principle indicates that this visualization strategy is applicable to a wide scope of polymer blends comprised of components with different rigidities and/or polarities.
Aggregation‐induced emission (AIE) refers to a photophysical effect that the luminescence of aggregates is stronger than that of the dispersed state. Since the concept of AIE was coined by Professor Ben Zhong Tang and co‐workers in 2001, AIE has evolved from a simple luminescent phenomenon to a multidisciplinary research field with a widespread influence. It has changed people's way of thinking about chromophore aggregation and greatly promoted the development of advanced luminescent materials. During the 20‐year development, diverse AIE luminogens (AIEgens) with attractive functionalities have been developed and remarkable achievements have been made in the mechanistic study and high‐tech applications of AIEgens. In this review, we provide an overview of the historical development and representative achievements of AIE research. Perspectives on the application of AIE in aggregate science are also briefly discussed to guide the future development in this field.
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