The regulation of emission color, emission efficiency and asymmetry factor is of great significance for the real applications of circularly polarized luminescent (CPL) materials. Herein, we develop a modular synthetic strategy toward full-color-tunable CPL materials based on chiral macrocyclic aggregation-induced emission (AIE) luminogens via delicate molecular engineering. Modular synthesis of chiral AIEgens with different acceptor moieties has afforded series of bright solid emitters with tunable emission colors. These chiral cyclic AIEgens have retained high solid state emission quantum yield and displayed CPL emission from blue to red as nano-aggregates, in liquid crystal matrix and polymer film. The strong acceptor units in the red-emitting chiral AIEgens RBTPE-2CN and SBTPE-2CN have rendered them twisted intramolecular charge transfer property and solvatochromic luminescence. And polymer matrix with different polarity further facilitates the tuning of CPL emission color from green to red emission. These results have paved a reliable approach toward constructing full-spectra solid-state CPL material.

Highly sensitive stimuli-responsive multifunctional luminescent materials are crucial for applications in optical sensing, high-level security, and anticounterfeiting. Here, we report two zero-dimensional (0D) hybrid copper(I) halides, (TEP) 2Cu 2Br 4 and (TEP) 2Cu 4Br 6, which are comprised of isolated [Cu 2Br 4] 2- and [Cu 4Br 6] 2- inorganic cluster units, respectively, separated by TEP + (TEP = tetraethylphosphonium) cations. (TEP) 2Cu 2Br 4 and (TEP) 2Cu 4Br 6 demonstrate ultrabright greenish-white and orange-red emissions, respectively, with near unity photoluminescence quantum yields. Optical spectroscopy measurements and density-functional theory (DFT) calculations reveal that photoemissions of these compounds originate from the formation of self-trapped excitons (STEs) due to the excited-state distortions in the copper(I) halide units. Single crystals of both compounds are radioluminescence (RL) active at room temperature under both X- and γ-rays exposure. The excellent energy resolution values and light yields up to 15,800 ph/MeV under 662 keV γ-rays of 137Cs suggest their potential for scintillation applications. Remarkably, (TEP) 2Cu 2Br 4 and (TEP) 2Cu 4Br 6 are interconvertible through external chemical stimuli or reverse crystallization. In addition, both compounds demonstrate luminescence on-off switching upon thermal stimuli. The sensitivity of (TEP) 2Cu 2Br 4 and (TEP) 2Cu 4Br 6 to the chemical and thermal stimuli coupled with their ultrabright emission allows their consideration for practical applications such as solid-state lighting, sensing, information storage, and anticounterfeiting.

Adsorbents with high adsorption efficiency and excellent biosafety for biomedical applications are highly required. MXene is a promising candidate owning these advantages, yet pristine MXene faces dilemmas including insufficient utility of surface site as well as limited processibility. Here, we develop MXene-encapsulated porous microcapsules via microfluidics. The microcapsules have a biomass hydrogel shell that provides a robust support for MXene in the core, by which the microcapsules are endowed with high MXene dosage and remarkable biosafety. Additionally, the MXene nanoflakes assemble into a three-dimension (3D) network via metal ion-induced gelation, thereby avoiding restacking and significantly improving surface utilization. Moreover, a freeze-pretreatment of the microcapsules during preparation results in the formation of a macroporous structure in the shell, which can facilitate the diffusion of the target molecules. These features, combined with additional magneto-responsiveness rendered by the incorporation of magnetic nanoparticles, contribute to prominent performances of the microcapsules in cleaning uremia toxins including creatinine, urea, and uric acid. Thus, it is anticipated that the MXene-encapsulated microcapsules will be promising adsorbents in dialysis-related applications, and the combination of microfluidic encapsulation with metal ion gelation will provide a novel approach for construction of hybrid MXene materials with desired functions.

Interview with Professor Guoqing Zhang

The side-chain has a significant effect on the optical properties and aggregation behaviors of the organic small molecule acceptors, which becomes an important strategy to optimize the photovoltaic performance of organic solar cells (OSCs). In this work, we designed and synthesized three novel nonfused ring electron acceptors (NFREAs) OC4-4Cl-Ph, OC4-4Cl-Th and OC4-4Cl-C8 with hexylbenzene, hexylthiophene and octyl side chains on the π-bridge units. Compared with OC4-4Cl-Ph and OC4-4Cl-Th, OC4-4Cl-C8 with linear alkyl side chain has more red-shift absorption, which is conducive to obtaining higher short-circuit current density. Additionally, the OC4-4Cl-C8 film exhibits a longer exciton diffusion distance and the D18:OC4-4Cl-C8 blend film displays faster hole transfer, weaker bimolecular recombination, and more efficient exciton transport. Furthermore, the D18:OC4-4Cl-C8 blend films can form good nano fibril-like interpenetrating networks, which can facilitate exciton dissociation and charge transport. Finally, OC4-4Cl-C8 based devices can generate an excellent PCE of 16.56%, which is much higher than OC4-4Cl-Ph (12.29%) and OC4-4Cl-Th based (11.00%) ones, being the highest PCE among the NFREA based binary devices. All in all, we have demonstrated that side-chain engineering is an efficient way to achieve high-performance NFREAs.

Amyloid-β peptide (Aβ) oligomers, characteristic symptom of Alzheimer’s disease (AD), have been identified as the most neurotoxic species and significant contributors to neurodegeneration in AD. However, due to their transient and heterogeneous nature, the high-resolution structures and exact pathogenic processes of Aβ oligomers are currently unknown. Using light-controlled molecular tweezers (LMTs), we describe a method for precisely capturing specific Aβ oligomers produced from synthetic Aβ and AD animal models. Light irradiation can activate LMTs, which are composed of two Aβ-targeting pentapeptides (KLVFF) motifs and a rigid azobenzene (azo) derivative, to form a tweezer-like cis configuration that preferentially binds to specifc oligomers matching the space of the tweezers via multivalent interactions of KLVFF motifs with the oligomers. Surprisingly, cis-LMTs can immobilize the captured oligomers in transgenic Caenorhabditis elegans (C. elegans) in vivo under light irradiation. The LMTs may serve as spatiotemporally controllable molecular tools to extract specific native oligomers for the structure and function studies via their reversible photoisomerization, which would improve the understanding of the toxic mechanisms of Aβ oligomers and development of oligomer-targeted diagnosis and therapy.

Fluorescent-magneto nanoemitters have gained considerable attention for their applications in mechanical controlling-assisted optical signaling. However, the incompatibility between magnetic and fluorescent components often leads to functional limitations in traditional magneto@fluorescence nanostructure. Herein, we introduce a new compact-discrete spatial arrangement on a “fluorescence@magneto” core–shell nanostructure consisting of a close-packed aggregation-induced emission luminogen (AIEgen) core and a discrete magnetic shell. This structural design effectively eliminates the optical and magnetic interferences between the dual components by facilitating AIEgens loading in core region and reducing the magnetic feeding amount through effective exposure of the magnetic units. Thereby, the resulting magneto-AIEgen nanoparticle (MANP) demonstrates “win-win” performances: (i) high fluorescent intensity contributed by AIEgens stacking-enhanced photoluminescence and reduced photons loss from the meager magnetic shell; (ii) marked magnetic activity due to magneto extraposition-minimized magnetic shielding. Accordingly, the dual functions-retained MANP provides a proof of concept for construction of an immunochromatographic sensing platform, where it enables bright fluorescent labeling after magnetically enriching and separating procalcitonin and lipoarabinomannan in clinical human serum and urine, respectively, for the clinical diagnosis of bacterial infections-caused inflammation and tuberculosis. This study not only inspires the rational design of magnetic-fluorescent nanoemitter, but also highlights promising potential in magneto-assisted point-of-care test and biomedicine applications.

Photoresponsive supramolecular materials have been fabricated by controlling the density of reversible cross-links or the distribution of movable cross-links. This study prepared photoresponsive polyurethane (CD-Azo-PU) based on controlling the crystallization of the hard segments in polyurethane (PU) by complexation between azobenzene (Azo) and cyclodextrins (CDs). CD-Azo-PU incorporated polyurethane as the main chain and a 1:2 inclusion complex between Azo and γCD as a movable crosslink point. Upon ultraviolet light (UV, λ = 365 nm) irradiation, the photoresponsiveness of CD-Azo-PU bent toward the light source (defined as positive), while that of the linear Azo polyurethane (Azo-LPU) without TAcγCD-diOH as a movable crosslinker bent in the direction opposite the light source. The bending rates were determined to be 0.058°/s for CD-Azo-PU and 0.027°/s for Azo-LPU, indicating that the bending rate for CD-Azo-PU was faster than that for Azo-LPU. By incorporating movable cross-links into CD-Azo-PU, we successfully achieved specific photoresponsive actuation with an enhanced rate.

The efficacy of nanoparticle (NP)-based drug delivery technology is hampered by aberrant tumor stromal microenvironments (TSMs) that hinder NP transportation. Therefore, the promotion of NP permeation into deep tumor sites via the regulation of tumor microenvironments is of critical importance. Herein, we propose a potential solution using a dihydrazidine (HDZ)-loaded nanoparticle drug delivery system containing a pH-responsive, cyclic RGD peptide-modified prodrug based on doxorubicin (cRGD-Dex-DOX). With a combined experimental and theoretical approach, we find that the designed NP system can recognize the acid tumor environments and precisely release the encapsulated HDZ into tumor tissues. HDZ can notably downregulate the expression levels of hypoxia-inducible factor 1α (HIF1α), α-smooth muscle actin, and fibronectin through the dilation of tumor blood vessels. These changes in the TSMs enhance the enrichment and penetration of NPs and also unexpectedly promote the infiltration of activated T cells into tumors, suggesting that such a system may offer an effective “multifunctional therapy” through both improving the chemotherapeutic effect and enhancing the immune response to tumors. In vivo experiments on 4T1 breast cancer bearing mice indeed validate that this therapy has the most outstanding antitumor effects over all the other tested control regimens, with the lowest side effects as well.

Centrifugal and shear forces are produced when solids or liquids rotate. Rotary systems and devices that use these forces, such as dynamic thin-film flow technology, are evolving continuously, improving material structure-property relationships at the nanoscale, representing a rapidly thriving and expanding field of research high with green chemistry metrics, consolidated at the inception of science. The vortex fluidic device (VFD) provides many advantages, with fluidic waves causing high shear and producing large surface areas for micro-mixing as well as rapid mass and heat transfer, enabling reactions beyond diffusion control in the processing. Combining these abilities allows for a green and innovative approach to altering materials for various research and industry applications by controlling small-scale flows and regulating molecular and macromolecular chemical reactivity, self-organization phenomena, and the synthesis of novel materials. This review highlights the aptitude of the VFD as clean technology, with an increase in efficiency for a diversity of top-down, bottom-up, and novel material transformations, benefiting from effective vortex-based processing for the transformation of material structure-property relationships.

Macroscopic chiral spherulites prepared by hierarchical self-assembly have attracted considerable attention due to their excellent property as chiroptical materials. However, preparing controllable handedness spherulites in bulk film remains a challenge due to the absent knowledge of the evolution mechanism from the molecule to macroscopic crystal during chiral assembly. In this contribution, we constructed chiral controllable macroscopic spherulites with circularly polarized luminescence (CPL) using enantiomeric tartaric acid and Rhodamine B co-assembled with liquid crystal block copolymers, poly (ethylene oxide)-b-poly (methyl methacrylate) bearing azobenzene group side chains. It was found that the chiral liquid crystal field induced by exogenous chiral molecules was closely related to the formation of macroscopic chiral spherulites. Moreover, the transformation of azobenzene cis-trans isomerization under photo-thermal endows films with adjustable CPL. This facile strategy provides a platform to design large-scale chiral structures for chiroptical switching, encryption, and memory storage materials.

Crosslinking thermosets with hyperbranched polymers confers them superior comprehensive performance. However, it still remains a further understanding of polymer crosslinking from the molecular chains to the role of aggregates. In this study, three hyperbranched polysiloxane structures (HBPSi-R) are synthesized as model macromolecules, each featuring distinct terminal groups (R denotes amino, epoxy, and vinyl groups) while similar molecular backbone (Si-O-C). These structures were subsequently copolymerized with epoxy monomers to construct interpenetrating HBPSi-R/epoxy/anhydride co-polymer systems. The spatial molecular configuration and flexible Si-O-C branches of HBPSi-R endow them with remarkable reinforcement and toughening effects. Notably, an optimum impact strength of 28.9 kJ mol-1 is achieved with a mere 3% loading of HBPSi-V, nearly three times that of the native epoxy (12.9 kJ mol-1). By contrasting the terminal effects, the aggregation states and crosslinking modes were proposed, thus clarifying the supramolecular-dominant aggregation mechanism and covalent-dominant dispersion mechanism, which influences the resulting material properties. This work underscores the significance of aggregate science in comprehending polymer crosslinking and provides theoretical insights for tailoring material properties at a refined molecular level in the field of polymer science.

Antibiotic resistance is a major challenge in the clinical treatment of bacterial infectious diseases. Herein, we constructed a multifunctional DNA nanoplatform as a versatile carrier for bacteria-specific delivery of clinical antibiotic ciprofloxacin (CIP) and classic nanoantibiotic silver nanoparticles (AgNP). In our rational design, CIP was efficiently loaded in the self-assembly double-bundle DNA tetrahedron through intercalation with DNA duplex, and single-strand DNA-modified AgNP was embedded in the cavity of the DNA tetrahedron through hybridization. With the site-specific assembly of targeting aptamer in the well-defined DNA tetrahedron, the bacteria-specific dual-antibiotic delivery system exhibited excellent combined bactericidal properties. With enhanced antibiotic accumulation through breaking the out membrane of bacteria, the antibiotic delivery system effectively inhibited biofilm formation and promoted the healing of infected wounds in vivo. This DNA-based antibiotic delivery system provides a promising strategy for the treatment of antibiotic-resistant infections.

Flame retardants play a crucial role in improving the flame retardant properties of polymer materials. In recent years, environmental problems caused by flame retardants have attracted widespread attention. It is urgent to use green and effective methods to prepare flame retardant polymers. Bioinspired nanocomposites with layered structures seem to provide an effective idea, but in general, the hydrophilic properties of their raw materials limit their applications in certain fields. Here, we prepared biomimetic composites with a layered “brick-and-mortar” structure by gravity-induced deposition using polyimide as the polymer matrix and montmorillonite (MMT) as the filler. The well-arranged structures of the composite material could isolate oxygen and prevent combustible gases from escaping. The gas barrier performance has been greatly improved, in which the water vapor transmission rate (WVTR) and the oxygen transmission rate (OTR) decreased by 99.18% and three orders of magnitude, respectively. The flame retardant performance has also been improved, and its limiting oxygen index can reach 67.9%. More importantly, the polyimide matrix can be converted to water-insoluble by thermal imidization of water-soluble poly (amic acid) salt precursors, which endows the composites with low hygroscopicity. Such coating containing MMT can protect against polyurethane (PU) foam from fire. During the conical calorimetric test, the coated sample self-extinguished, and the peak heat release rate, total heat release, total smoke production is significantly decreased by 53.39%, 40.69%, and 53.03%, respectively. Taking advantage of these properties, this work utilizes a facile method to prepare biomimetic composites with low moisture absorption, excellent gas barrier properties, and flame retardancy, which have great application potential.

Aggregation-Induced Emission (AIE) is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known Aggregation-Caused Quenching (ACQ). AIE has the potential to be utilized in the large-scale production of AIE-active polymeric materials because of their wide range of practical applications such as stimuli-responsive sensors, biological imaging agents, and drug delivery systems. This is evident from the increasing number of publications over the years since AIE was first discovered. In addition, the ever-growing interest in this field has led many researchers around the world to develop new and creative methods in the design of monomers, initiators and crosslinkers, with the goal of broadening the scope and utility of AIE polymers. One of the most promising approaches to the design and synthesis of AIE polymers is the use of the Reversible-Deactivation Radical Polymerization (RDRP) techniques, which enabled the production of well-controlled AIE materials that are often difficult to achieve by other methods. In this review, a summary of some recent works that utilize RDRP for AIE polymer design and synthesis is presented, including (1) the design of AIE-related monomers, initiators/crosslinkers; the achievements in preparation of AIE polymers using (2) Reversible Addition-Fragmentation Chain Transfer (RAFT) technique; (3) Atom Transfer Radical Polymerization (ATRP) technique; (4) other techniques such as Cu(0)-RDRP technique and Nitroxide-Mediated Polymerization (NMP) technique; (5) the possible applications of these AIE polymers and finally (6) a summary/perspective and the future direction of AIE polymers.

The development of green and simple chemiluminescence (CL) systems with intensive and long-lasting emission is highly desirable in lighting and extension of their applications. In this study, it is found that the involvement of aggregation-induced emission (AIE) surfactant could greatly enhance the CL of luminol–H2O2–Co2+ system. The inserted hydrophobic tetraphenylethylene fluorophore in AIE is able to increase the hydrophobicity of alkyl chain and decrease the critical micelle concentration (CMC) of surfactant. The synergistic effect of micelle-improved enrichment and CL resonance energy transfer endows luminol–H2O2–Co2+ system intensive and long-lasting emission under neutral pH conditions (pH 7.4). The visible emission is still observed even after 60 min. Our study has opened a new avenue for exploring green and simple effective CL systems through AIE surfactant with unltralow CMC toward various applications in lighting, optical sensing, and photocatalysis, etc.

Molecular aggregation affects the electronic interactions between molecules and has emerged as a powerful tool in material science. Molecular aggregation finds wide applications in the research of new physical effects; however, its value for chemical reaction development has been far less explored. Herein, we report the development of aggregation-enabled alkene insertion into carbon–halogen bonds. The spontaneous cleavage of C–X (X = Cl, Br, or I) bonds generates an intimate ion pair, which can be quickly captured by alkenes in the aggregated state. Additional catalysts or promoters are not necessary under such circumstances, and solvent quenching experiments indicate that the aggregated state is critical for initiating such sequences. The ionic insertion mode and the intimate ion pair mechanism are supported by mechanistic studies, density functional theory calculations, and symmetry-adapted perturbation theory analysis. Results show that the non-aggregated state may quench the transition state and terminate the insertion process.

Direct visualization of polymer crystalline structure remains challenging due to the lack of contrast across different microphases of polymers. Here we address this conundrum using an aggregation-induced emission luminogen (AIEgen) with confinement fluorescence effect, which could be used as a “built-in” sensor to label different crystalline phases. Computational simulations reveal that the confined space induces the AIEgens to take a more planar conformation, resulting in a red-shifted emission spectrum. With this property, the information of various polymer crystalline forms is converted into different fluorescence colors, which is attributed to the different spatial dimensions of the polymer amorphous layer between lamellar crystals where the AIEgens are located. Finally, polymer crystalline phases distinction, quantitative crystallinity determination, and stereocomplex crystals visualization are achieved, providing a relationship between crystalline microstructure and fluorescence signals. This work demonstrates the potential of AIE fluorescence technology in polymer science, providing a theoretical and experimental guideline for the materials processing and optimization of mechanical performance.