Macroscale Conjugated Microporous Polymers: Controlling Versatile Functionalities Over Several Dimensions

A robust triphenylamine-based monolithic polymer network for selective sieving of CO2 and PM from flue gas

The increasingly urgent issue of climate change is driving the development of carbon dioxide (CO2) capture and separation technologies in flue gas after combustion. The monolithic adsorbent stands out in practical adsorption applications for its simplified powder compaction process while maintaining the inherent balance between energy consumption for regeneration and selectivity for adsorption. However, optimizing the adsorption capacity and selectivity of CO2 separation materials remains a significant challenge. Herein, we synthesized monolithic polymer networks (N-CMPs) with triphenylamine adsorption sites, acid-base environment tolerance, and precise narrow microchannel pore systems for the selective sieving of CO2 and particulate matter (PM) in flue gas. The inherent continuous covalent bonding of N-CMPs, along with their highly delocalized π-π conjugated porous framework, ensures the stability of the monolithic polymer network's adsorption and separation capabilities under wet and acid-base conditions. Specifically, under the conditions of 1 bar at 273 K, the CO2 adsorption capacity of N-CMP-1 is 3.35 mmol/g. Attributed to the highly polar environment generated by triphenylamine and the inherent high micropore/mesopore ratio, N-CMPs exhibit an excellent ideal adsorbed solution theory (IAST) selectivity for CO2/N2 under simulated flue gas conditions (CO2/N2 = 15:85). Dynamic breakthrough experiments further visualize the high separation efficiency of N-CMPs in practical adsorption applications. Moreover, under acid-base conditions, N-CMPs achieve a capture efficiency exceeding 99.76 % for PM0.3, enabling the selective separation of CO2 and PM in flue gas. In fact, the combined capture of hazardous PM and CO2 from the exhaust gases produced by the combustion of fossil fuels will play a pivotal role in mitigating climate change and environmental issues until low-carbon and alternative energy technologies are widely adopted.

Hydroxyl-containing triazine-based conjugated microporous polymers for solid phase extraction of fluoroquinolone antibiotics in the environment and food samples

Fluoroquinolones (FQs) are a category of broadly used antibiotics. Development of an effective and sensitive approach for determination of trace FQs in environmental and food samples is still challenging. Herein, the hydroxyl-containing triazine-based conjugated microporous polymers (CMPs-OH) was constructed and served as SPE absorbent for the efficient enrichment of FQs. Based on DFT simulations, the excellent enrichment capacity between CMPs-OH and FQs was contributed by hydrogen bonding and π-π interactions. In combination with high-performance liquid chromatography-tandem mass spectrometry, the proposed approach exhibited a wide linear range (0.2-400 ng L-1), low detection limits (0.05-0.15 ng L-1), and good intraday and interday precisions under optimal conditions. In addition, the established method was effectively utilized for the determination of FQs in fourteen samples with recoveries between 82.6 % and 109.2 %. This work provided a feasible sample pretreatment method for monitoring FQs in environmental and food matrices.

A microporous polymer based on nonconjugated hindered biphenyls that emits blue light

Microporous organic polymers that have three-dimensional connectivity stemming from monomers with tetrahedral or tetrahedron-like geometry can have high surface areas and strong fluorescence. There are however few examples of such polymers based on hindered biaryls, and their fluorescence has not been studied. Hypothesizing that the contortion in a hindered biphenyl moiety would modulate the optical properties of a polymer built from it, we synthesized a meta-enchained polyphenylene from a 2,2',6,6'-tetramethylbiphenyl-based monomer, in which the two phenyl rings are nearly mutually perpendicular. The polymer was microporous with SBET = 495 m2 g-1. The polymer absorbed near-UV light and emitted blue fluorescence despite the meta-enchainment that would have been expected to break the conjugation. A related copolymer, synthesized from 2,2',6,6'-tetramethylbiphenyl-based and unsubstituted biphenyl-based monomers, was microporous but not fluorescent.

Versatile Hyper-Cross-Linked Polymers Derived from Waste Polystyrene: Synthesis, Properties, and Intentional Recycling

Waste polystyrene contributes considerably to environmental pollution due to its persistent nature, prompting a widespread consensus on the urgent need for viable recycling solutions. Owing to the aromatic groups structure of polystyrene, hyper-cross-linked polymers can be synthesized through the Friedel-Crafts cross-linking reaction using Lewis acids as catalysts. In addition, hyper-cross-linked polystyrene and its carbonaceous counterparts can be used in several important applications, which helps in their efficient recycling. This review systematically explores methods for preparing multifunctional hyper-cross-linked polymers from waste polystyrene and their applications in sustainable recycling. We have comprehensively outlined various synthetic approaches for these polymers and investigated their physical and chemical properties. These multifunctional polymers not only exhibit structural flexibility but also demonstrate diversity in performance, making them suitable for various applications. Through a systematic examination of synthetic methods, we showcase the cutting-edge positions of these materials in the field of hyper-cross-linked polymers. Additionally, we provide in-depth insights into the potential applications of these hyper-cross-linked polymers in intentional recycling, highlighting their important contributions to environmental protection and sustainable development. This research provides valuable references to the fields of sustainable materials science and waste management, encouraging further exploration of innovative approaches for the utilization of discarded polystyrene.

Application of chiral recyclable catalysts in asymmetric catalysis

Chiral drugs hold a significant position within the contemporary pharmaceutical market, and the chiral catalysts play a crucial role in their synthesis. However, current chiral catalysts encounter challenges pertaining to their separation from products and the recycling process. The utilization of chiral recyclable catalysts not only reduces production costs but also aligns with the growing emphasis on environmentally-friendly chiral synthetic chemistry. These recyclable catalysts exhibit diverse carriers and distinct characteristics. Chemists employ the distinctive attributes of individual carriers to render them recyclable, thereby yielding time and cost savings. This review examines the asymmetric recyclable catalytic reactions reported between January 2017 and October 2023, categorizing them based on carrier solubility, and elucidates the loading techniques, catalytic impacts, recovery approaches, and recycling processes associated with these carriers.

Nanofibrous Porous Organic Polymers and Their Derivatives: From Synthesis to Applications

Engineering porous organic polymers (POPs) into 1D morphology holds significant promise for diverse applications due to their exceptional processability and increased surface contact for enhanced interactions with guest molecules. This article reviews the latest developments in nanofibrous POPs and their derivatives, encompassing porous organic polymer nanofibers, their composites, and POPs-derived carbon nanofibers. The review delves into the design and fabrication strategies, elucidates the formation mechanisms, explores their functional attributes, and highlights promising applications. The first section systematically outlines two primary fabrication approaches of nanofibrous POPs, i.e., direct bulk synthesis and electrospinning technology. Both routes are discussed and compared in terms of template utilization and post-treatments. Next, performance of nanofibrous POPs and their derivatives are reviewed for applications including water treatment, water/oil separation, gas adsorption, energy storage, heterogeneous catalysis, microwave absorption, and biomedical systems. Finally, highlighting existent challenges and offering future prospects of nanofibrous POPs and their derivatives are concluded.

Powders to Thin Films: Advances in Conjugated Microporous Polymer Chemical Sensors

Chemical sensing of harmful species released either from natural or anthropogenic activities is critical to ensuring human safety and health. Over the last decade, conjugated microporous polymers (CMPs) have been proven to be potential sensor materials with the possibility of realizing sensing devices for practical applications. CMPs found to be unique among other porous materials such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) due to their high chemical/thermal stability, high surface area, microporosity, efficient host-guest interactions with the analyte, efficient exciton migration along the π-conjugated chains, and tailorable structure to target specific analytes. Several CMP-based optical, electrochemical, colorimetric, and ratiometric sensors with excellent selectivity and sensing performance were reported. This review comprehensively discusses the advances in CMP chemical sensors (powders and thin films) in the detection of nitroaromatic explosives, chemical warfare agents, anions, metal ions, biomolecules, iodine, and volatile organic compounds (VOCs), with simultaneous delineation of design strategy principles guiding the selectivity and sensitivity of CMP. Preceding this, various photophysical mechanisms responsible for chemical sensing are discussed in detail for convenience. Finally, future challenges to be addressed in the field of CMP chemical sensors are discussed.

Mimicking Bidirectional Inhibitory Synapse Using a Porous-Confined Ionic Memristor with Electrolyte/Tris(4-aminophenyl)amine Neurotransmitter

Ionic memristors can emulate brain-like functions of biological synapses for neuromorphic technologies. Apart from the widely studied excitatory-excitatory and excitatory-inhibitory synapses, reports on memristors with the inhibitory-inhibitory synaptic behaviors remain a challenge. Here, the first biaxially inhibited artificial synapse is demonstrated, consisting of a solid electrolyte and conjugated microporous polymers bilayer as neurotransmitter, with the former serving as an ion reservoir and the latter acting as a confined transport. Due to the migration, trapping, and de-trapping of ions within the nanoslits, the device poses inhibitory synaptic plasticity under both positive and negative stimuli. Remarkably, the artificial synapse is able to maintain a low level of stable nonvolatile memory over a long period of time (≈60 min) after multiple stimuli, with feature-inferencing/-training capabilities of neural node in neuromorphic computing. This work paves a reliable strategy for constructing nanochannel ionic memristive materials toward fully inhibitory synaptic devices.

Electrochemical coupling in subnanometer pores/channels for rechargeable batteries

Subnanometer pores/channels (SNPCs) play crucial roles in regulating electrochemical redox reactions for rechargeable batteries. The delicately designed and tailored porous structure of SNPCs not only provides ample space for ion storage but also facilitates efficient ion diffusion within the electrodes in batteries, which can greatly improve the electrochemical performance. However, due to current technological limitations, it is challenging to synthesize and control the quality, storage, and transport of nanopores at the subnanometer scale, as well as to understand the relationship between SNPCs and performances. In this review, we systematically classify and summarize materials with SNPCs from a structural perspective, dividing them into one-dimensional (1D) SNPCs, two-dimensional (2D) SNPCs, and three-dimensional (3D) SNPCs. We also unveil the unique physicochemical properties of SNPCs and analyse electrochemical couplings in SNPCs for rechargeable batteries, including cathodes, anodes, electrolytes, and functional materials. Finally, we discuss the challenges that SNPCs may face in electrochemical reactions in batteries and propose future research directions.

Ultra-stable hollow nanotube conjugated microporous polymer incorporating fluorenyl moieties for Co-capture of PM and CO2

Conjugated microporous polymers have a highly delocalized π-π conjugated porous skeleton connected by covalent bonds, which can combine their excellent stability with high adsorption, in order to be applied to the study of co-capture of harmful particulate matter (PM) and carbon dioxide (CO2) under high temperature and high humidity conditions. In this paper, fluorene-based coupled conjugated microporous polymers (D-CMPs) with functionalized hollow nanotubes and abundant microporous structures were proposed. Through mechanism exploration and molecular electrostatic potential (MESP) calculation, the capture efficiency, adsorption capacity and selectivity of PM and CO2 in the waste gas stream of carbon-based combustion were analyzed. The results indicate that D-CMPs, with their rigid carbon-based π-conjugated framework, exhibit excellent tolerance under prolonged high-humidity conditions, with a capture efficiency exceeding 99.87% for PM0.3 and exceeding 99.99% for PM2.5. Meanwhile, based on its chemical/thermal stability, it can realize the recycling of adsorption-regeneration. On this basis, the "slip effect" induced by the open three-dimensional hierarchical porous structure of D-CMPs significantly enhances airflow dispersion and improves gas throughput (with a minimal permeation resistance of only 15 Pa). At a pressure of 1 bar and a temperature of 273.15 K, D-CMP-2 exhibited a CO2 adsorption capacity of up to 2.69 mmol g-1. The fitting results of three isothermal adsorption models demonstrate that D-CMPs exhibit an outstanding equilibrium selectivity towards CO2. Therefore, prior to the widespread adoption of low-carbon and clean energy technologies, porous solid materials exhibiting excellent structural stability, equilibrium selectivity, environmental tolerance, and high adsorption capacity emerge as optimal candidates for the treatment of industrial waste gases.

Delocalization Engineering of Heme-Mimetic Artificial Enzymes for Augmented Reactive Oxygen Catalysis

Developing artificial enzymes based on organic molecules or polymers for reactive oxygen species (ROS)-related catalysis has broad applicability. Herein, inspired by porphyrin-based heme mimics, we report the synthesis of polyphthalocyanine-based conjugated polymers (Fe-PPc-AE) as a new porphyrin-evolving structure to serve as efficient and versatile artificial enzymes for augmented reactive oxygen catalysis. Owing to the structural advantages, such as enhanced π-conjugation networks and π-electron delocalization, promoted electron transfer, and unique Fe-N coordination centers, Fe-PPc-AE showed more efficient ROS-production activity in terms of Vmax and turnover numbers as compared with porphyrin-based conjugated polymers (Fe-PPor-AE), which also surpassed reported state-of-the-art artificial enzymes in their activity. More interestingly, by changing the reaction medium and substrates, Fe-PPc-AE also revealed significantly improved activity and environmental adaptivity in many other ROS-related biocatalytic processes, validating the potential of Fe-PPc-AE to replace conventional (poly)porphyrin-based heme mimics for ROS-related catalysis, biosensors, or biotherapeutics. It is suggested that this study will offer essential guidance for designing artificial enzymes based on organic molecules or polymers.

Durable superhydrophobic surface in wearable sensors: From nature to application

The current generation of wearable sensors often experiences signal interference and external corrosion, leading to device degradation and failure. To address these challenges, the biomimetic superhydrophobic approach has been developed, which offers self-cleaning, low adhesion, corrosion resistance, anti-interference, and other properties. Such surfaces possess hierarchical nanostructures and low surface energy, resulting in a smaller contact area with the skin or external environment. Liquid droplets can even become suspended outside the flexible electronics, reducing the risk of pollution and signal interference, which contributes to the long-term stability of the device in complex environments. Additionally, the coupling of superhydrophobic surfaces and flexible electronics can potentially enhance the device performance due to their large specific surface area and low surface energy. However, the fragility of layered textures in various scenarios and the lack of standardized evaluation and testing methods limit the industrial production of superhydrophobic wearable sensors. This review provides an overview of recent research on superhydrophobic flexible wearable sensors, including the fabrication methodology, evaluation, and specific application targets. The processing, performance, and characteristics of superhydrophobic surfaces are discussed, as well as the working mechanisms and potential challenges of superhydrophobic flexible electronics. Moreover, evaluation strategies for application-oriented superhydrophobic surfaces are presented.

Continuous-Flow Catalysis Using Phosphine-Metal Complexes on Porous Polymers: Designing Ligands, Pores, and Reactors

Continuous-flow syntheses using immobilized catalysts can offer efficient chemical processes with easy separation and purification. Porous polymers have gained significant interests for their applications to catalytic systems in the field of organic chemistry. The porous polymers are recognized for their large surface area, high chemical stability, facile modulation of surface chemistry, and cost-effectiveness. It is crucial to immobilize transition-metal catalysts due to their difficult separation and high toxicity. Supported phosphine ligands represent a noteworthy system for the effective immobilization of metal catalysts and modulation of catalytic properties. Researchers have been actively pursuing strategies involving phosphine-metal complexes supported on porous polymers, aiming for high activities, durabilities, selectivities, and applicability to continuous-flow systems. This review provides a concise overview of phosphine-metal complexes supported on porous polymers for continuous-flow catalytic reactions. Polymer catalysts are categorized based on pore sizes, including micro-, meso-, and macroporous polymers. The characteristics of these porous polymers are explored concerning their efficiency in immobilized catalysis and continuous-flow systems.

Highlights in Interface of Wastewater Treatment by Utilizing Metal Organic Frameworks: Purification and Adsorption Kinetics

Polluted water has become a concern for the scientific community as it causes many severe threats to living beings. Detection or removal of contaminants present in wastewater and attaining purity of water that can be used for various purposes are a primary responsibility. Different treatment methods have already been used for the purification of sewage. There is a need for low-cost, highly selective, and reusable materials that can efficiently remove pollutants or purify contaminated water. In this regard, MOFs have shown significant potential for applications such as supercapacitors, drug delivery, gas storage, pollutant adsorption, etc. The outstanding structural diversity, substantial surface areas, and adjustable pore sizes of MOFs make them superior candidates for wastewater treatment. This Review provides an overview of the interaction science and engineering (kinetic and thermodynamic aspects with interactions) underpinning MOFs for water purification. First, fundamental strategies for the synthesis methods of MOFs, different categories, and their applicability in wastewater treatment are summarized, followed by a detailed explanation of various interaction mechanisms. Finally, current challenges and future outlooks for research on MOF materials toward the adsorption of hazardous components are discussed. A new avenue for modifying their structural characteristics for the adsorption and separation of hazardous materials, which will undoubtedly direct future work, is also summarized.

Selective Adsorption Behavior of Sulfuric Acid Oxidized and Doped Conjugated Microporous Poly(aniline)s toward Lead Ions in an Aqueous Environment

The coexistence of lead, zinc, and copper ions in wastewater constitutes an environmental challenge of pressing concern. This research delves into the preparation of innovative oxidation-doped conjugated microporous poly(aniline) frameworks, exploring their prospective efficacy in regulating lead ion adsorption from aqueous solutions. H2SO4-CMPTA demonstrates the capability to reach adsorption equilibrium within 15 min at a lead concentration of 50 ppm. Even at a lead concentration of 20 ppm, it still efficaciously attenuates these levels to sub-10 ppb, a value surpassing extant standard. H2SO4-CMPTA retains over 78.8% adsorption efficiency after six cycles. Analytical characterization coupled with computational calculations suggests that sulfate-coordinated nitrogen cationic structure plays a crucial role in adsorption. A deeper investigation reveals the cardinal role of electrostatic attraction and exclusive chelation adsorption underpinning the efficient capture of lead ions by doped sulfate ions. Intriguingly, in a mixed heavy metal solution containing lead, zinc, and copper ions, H2SO4-CMPTA exhibits an initial predilection toward zinc ions, yet an eventual ion-exchange adsorption gravitating toward lead ions was discerned, governed by the latter's superior binding energy. Our study elucidates a promising material as an efficacious tool for the remediation of aquatic environments tainted with lead contaminants.

Robust synthesis of free-standing films comprising conjugated microporous polymers nanotubes for water disinfection

Water environmental pollution especially caused by bacteria, viruses and other microorganisms always would accelerate the spread of infectious diseases and has been one of the issues highly concerned by the World Health Organization for a long time. The development of novel antibacterial materials with high activity for water cleanness was of great importance for public health and ecological sustainable development. In this work, we developed two really free-standing conjugated microprous polymers (CMPs) film with large size and processibility by a simple and convenient solid surface-assisted polymerization between bromo- and aryl-acetylene monomers. With the solid interfacial orientation from silica nanofibers, the resulting CMPs film exhibited nanotube-liked morphology with BET surface area of 379.5 m2 g-1 and 480.1 m2 g-1. The introduction of antibacterial isocyanurate and acetanilide group into polymer skeleton brings the resulting CMPs film intrinsically antimicrobial capability and durability. The growth of E. coli can be completely inhibited by the resulting CMPs film even after several cycles. Our work was suggested to provide a new route for rational design of CMPs film or membrane with antibacterial activity for water treatment and sterilization.

Hollow Ru/RuO2 nanospheres with nanoparticulate shells for high performance electrocatalytic oxygen evolution reactions

This work shows that hollow Ru/RuO2 nanoparticles having nanoparticulate shells (HN-Ru/RuO2) can be prepared using hollow microporous organic polymers with Ru species (H-MOP-Ru) as precursors. Using silica spheres as templates, H-MOPs were prepared through the Sonogashira-Hagihara coupling of 1,3,5-triethynylbenzene with 2,3-ethoxymethylenedioxy-1,4-diiodobenzene. Acid hydrolysis of cyclic ethyl orthoformate protecting groups generated catechol moieties to form H-MOP-Cat. Then, H-MOP-Ru was obtained by incorporating Ru species into H-MOP-Cat. Heat-treatment of H-MOP-Ru under air induced the formation of HN-Ru/RuO2 with a diameter of 61 nm and shells consisting of 6-7 nm nanoparticles. Due to the hollow structure and nanoparticulate shells, HN-Ru/RuO2 showed a high surface area of 80 m2 g-1 and a pore volume of 0.18 cm3 g-1. The HN-Ru/RuO2 showed enhanced electrocatalytic performance for the oxygen evolution reaction (OER) with an overpotential of 295 mV @ 10 mA cm-2 and a Tafel slope of 46 mV dec-1 in alkaline electrolyte, compared with control RuO2 such as commercial Ru/RuO2 nanoparticles (A-Ru/RuO2) and home-made Ru/RuO2 nanoparticles (N-Ru/RuO2) prepared via the same synthetic procedure as HN-Ru/RuO2. While HN-Ru/RuO2 inevitably contained Pd originated from coupling catalysts, it showed superior performance to Ru/RuO2 nanoparticles with the same Pd content (N1-Ru/RuO2), indicating that the efficient electrocatalytic performance of HN-Ru/RuO2 is attributable to its hollow structure and nanoparticulate shells.

General Approach to Construct C-C Single Bond-Linked Covalent Organic Frameworks

C-C single bond-linked covalent organic frameworks (CSBL-COFs) are extremely needed because of their excellent stabilities and potential applications in harsh conditions. However, strategies to generate CSBL-COFs are limited to the acetylenic self-homocoupling Glaser-Hay reaction or post-synthetic reduction of vinylene-based COFs. Exploring new strategies to expand the realm of CSBL-COFs is urgently needed but extremely challenging. To address the synthetic challenges, we for the first time developed a general approach via the reaction between aromatic aldehydes and active methyl group-involving monomers with enhanced acidity, which realized the successful construction of a series of CSBL-COFs. As expected, the obtained CSBL-COFs exhibited outstanding chemical stability, which can stabilize in 6 M NaOH, 3 M HCl, boiling water, and 100 mg/mL NaBH4 for at least 3 days. It is important to mention that CSBL-COFs possess a large amount of ionic sites distributed throughout the networks; gentle shaking allowed our COFs to easily self-disperse as nanoparticles and suspend in water for at least 12 h without reprecipitating. As far as we know, such self-dispersed COFs with high water dispersity are rare to date, and few examples are mainly limited to the guanidinium- and pseudorotaxane-based COFs. Our work thus developed a family of self-dispersed COFs for potential applications in different sorts of fields. Our contribution would thus pave a new avenue for constructing a broader class of CSBL-COFs for their wide applications in various fields.

Conjugated Microporous Polymers Based on Octet and Tetratopic Linkers for Efficient Iodine Capture

Radioactive iodine from nuclear waste poses a huge threat to public safety and raises concerns about environmental pollution. There is thus a growing demand for developing novel adsorbents for highly effective iodine capture. In this work, we design and synthesize three novel conjugated microporous polymers, namely, TPE-PyTTA-CMP, TPE-TAPP-CMP, and TPE-TPDA-CMP, which are constructed by an imidization reaction based on octet and tetratopic linkers. The iodine vapor adsorption experiments show that the three CMPs have an excellent iodine adsorption capacity as high as 3.10, 3.67, and 4.68 g·g-1 under 348 K and ambient pressure conditions, respectively. The adsorbed iodine in the CMPs can be released into methanol in a dramatically rapid manner, and their excellent iodine adsorption performance can still be maintained after multiple cycles. In addition, the CMPs demonstrate good adsorption performance in an n-hexane solution of iodine, and the kinetic experimental data follow the pseudo-second-order model. The hierarchical porosity, extended π-conjugated skeleton, and rich electron-donor nitrogen sites of the CMPs could contribute to their excellent iodine adsorption performance. The knowledge information obtained in this work could open up new possibilities for designing novel CMPs targeting a wide range of environment-related applications.

Poly (Ionic Liquid)-Metal Organic Framework-Derived Nanoporous Carbon Membranes: Facile Fabrication and Ultrahigh Areal Capacitance

With the rapid development of energy storage technology, the operation of portable and wearable devices is inseparable from high energy density power supplies. However, the demand for high performance supercapacitors in movable smart electronics is still restrained by their insufficient areal capacitance and limited power/energy densities. In addition, some electroactive materials, including metal oxides, conductive polymers, graphene, porous carbons, etc., are inevitable to use extra adhesives for the preparation of electrode materials. In this work, integrated hierarchical graphitic porous carbon membranes used as the electrodes without adhesives are successfully synthesized, via pyrolyzing poly(ionic liquid)s (PILs)-metal organic frameworks (MOFs) composite membranes. The asymmetric supercapacitor is assembled by the carbonized PIL-MOF composite membrane and PILs-derived porous carbon membrane, and exhibits significant areal capacitance with remarkable power and energy densities. In the two-electrode system, the areal capacitance can reach 9.5 F cm-2 with an energy density of 1.91 mWh cm-2 . In the fabricated all-solid-state supercapacitors, the areal capacitance and energy density achieved 3.2 F cm-2 and 0.65 mWh cm-2 , respectively, exceeding most reported ones. Therefore, the integrated carbon membrane electrodes with high areal capacitance reveal great potential in miniaturized devices, and further show a wider application scope through regulating PILs.

Aggregates-based fluorescence sensing technology for food hazard detection: Principles, improvement strategies, and applications

Aggregates often exhibit modified or completely new properties compared with their molecular elements, making them an extraordinarily advantageous form of materials. The fluorescence signal change characteristics resulting from molecular aggregation endow aggregates with high sensitivity and broad applicability. In molecular aggregates, the photoluminescence properties at the molecular level can be annihilated or elevated, leading to aggregation-causing quenching (ACQ) or aggregation-induced emission (AIE) effects. This change in photoluminescence properties can be intelligently introduced in food hazard detection. Recognition units can combine with the aggregate-based sensor by joining the aggregation process, endowing the sensor with the high specificity of analytes (such as mycotoxins, pathogens, and complex organic molecules). In this review, aggregation mechanisms, structural characteristics of fluorescent materials (including ACQ/AIE-activated), and their applications in food hazard detection (with/without recognition units) are summarized. Because the design of aggregate-based sensors may be influenced by the properties of their components, the sensing mechanisms of different fluorescent materials were described separately. Details of fluorescent materials, including conventional organic dyes, carbon nanomaterials, quantum dots, polymers and polymer-based nanostructures and metal nanoclusters, and recognition units, such as aptamer, antibody, molecular imprinting, and host-guest recognition, are discussed. In addition, future trends of developing aggregate-based fluorescence sensing technology in monitoring food hazards are also proposed.

Rational Design of Bifunctional Microporous Organic Polymers Containing Anthracene and Triphenylamine Units for Energy Storage and Biological Applications

In this study, we synthesized two conjugated microporous polymers (CMPs), An-Ph-TPA and An-Ph-Py CMPs, using the Suzuki cross-coupling reaction. These CMPs are organic polymers with p-conjugated skeletons and persistent micro-porosity and contain anthracene (An) moieties linked to triphenylamine (TPA) and pyrene (Py) units. We characterized the chemical structures, porosities, thermal stabilities, and morphologies of the newly synthesized An-CMPs using spectroscopic, microscopic, and N₂ adsorption/desorption isotherm techniques. Our results from thermogravimetric analysis (TGA) showed that the An-Ph-TPA CMP displayed better thermal stability with T_d10 = 467 °C and char yield of 57 wt% compared to the An-Ph-Py CMP with T_d10 = 355 °C and char yield of 54 wt%. Furthermore, we evaluated the electrochemical performance of the An-linked CMPs and found that the An-Ph-TPA CMP had a higher capacitance of 116 F g^-1 and better capacitance stability of 97% over 5000 cycles at 10 A g^-1. In addition, we assessed the biocompatibility and cytotoxicity of An-linked CMPs using the MTT assay and a live/dead cell viability assay and observed that they were non-toxic and biocompatible with high cell viability values after 24 or 48 h of incubation. These findings suggest that the An-based CMPs synthesized in this study have potential applications in electrochemical testing and the biological field.

Ultramicroporous Polyphenylenes via Diels-Alder Polycondensation Approach

Development of new microporous organic polymers attracts significant attention due to a wide scope of promising applications. In addition, the synthesis of soluble, non-crosslinking polymers of high surface area and uniform microporosity is very challenging, and the methods for soluble microporous polymers formation are rather limited. In this work, we report a new approach to construct porous polyphenylenes which employs the Diels-Alder polycondensation of multifunctional ethynyl-containing monomers of different spatial architecture with bis(cyclopentadienone)s. The resulting polymers were soluble in common organic solvents, and their structure and properties were assessed by NMR, TGA, DSC, and SEC studies. The polymers demonstrated a specific surface area up to 751 m²·g^-1 and ultramicroporous (pore size ≤ 0.6 nm) structure. N₂ and CO₂ adsorption-desorption data revealed that porosity parameters, e.g., specific surface area and pore sizes, can be tuned selectively by varying the type of monomers and reaction conditions.

Carbazole-Involved Conjugated Microporous Polymer Hollow Spheres for Selective Photocatalytic Oxidation of Benzyl Alcohol under Visible-Light Irradiation

Conjugated microporous polymers (CMPs) have been considered a type of promising visible-light-driven, organic photocatalysts. However, apart from designing high-performance CMPs from a molecular perspective, little attention is paid to improving the photocatalytic properties of these polymers through macrostructural regulation. Herein, we prepared a kind of hollow spherical CMPs involving carbazole monomers and studied their performance on the selective photocatalytic oxidation of benzyl alcohol under visible light irradiation. The results demonstrate that the introduction of a hollow spherical structure improves the physicochemical properties of the as-designed CMPs, including the specific surface areas, optoelectronic characteristics, as well as photocatalytic performance, etc. In particular, the hollow CMPs can more effectively oxidize benzyl alcohol compared to pristine ones under blue light illumination, and produce >1 mmol of benzaldehyde in 4.5 h with a yield of up to 9 mmol·g^-1·h^-1, which is almost 5 times higher than that of the pristine ones. Furthermore, such hollow architecture has a similar enhanced effect on the oxidation of some other aromatic alcohols. This work shows that the deliberate construction of specific macrostructures can better arouse the photocatalytic activity of the as-designed CMPs, which will contribute to the further use of these organic polymer semiconductors in photocatalysis areas.

Covalent Pyrimidine Frameworks via a Tandem Polycondensation Method for Photocatalytic Hydrogen Production and Proton Conduction

The development of heteroaromatic conjugated porous polymers (H-CPPs) have received enormous research interests, because of the important functional roles of the heteroatoms in photocatalysis and proton conduction. However, due to the synthetic challenges deriving from the stable structures, the structural diversity and synthetic methods of them are still limited. Herein, a new type of H-CPPs, covalent pyrimidine frameworks (CPFs), via an efficient tandem polycondensation reaction between aldehyde, acetyl, and amidine monomers is reported. The resulting CPFs are bridged by pyrimidine units, rich of nitrogen atoms and can be structurally regulated on demand. The CPFs are shown to be active photocatalysts for hydrogen evolution from methanol via a photo-thermo-catalysis process, achieving an excellent hydrogen evolution rate of 5282.8 µmol h^-1  g^-1 . The CPFs can be further processed into a mixed matrix membrane, displaying an excellent proton conductivity of 1.30 × 10^-2  S cm^-1 at 413 K under anhydrous condition.

Impact of Interfaces, and Nanostructure on the Performance of Conjugated Polymer Photocatalysts for Hydrogen Production from Water

The direct conversion of sunlight into hydrogen through water splitting, and by converting carbon dioxide into useful chemical building blocks and fuels, has been an active area of research since early reports in the 1970s. Most of the semiconductors that drive these photocatalytic processes have been inorganic semiconductors, but since the first report of carbon nitride organic semiconductors have also been considered. Conjugated materials have been relatively extensively studied as photocatalysts for solar fuels generation over the last 5 years due to the synthetic control over composition and properties. The understanding of materials' properties, its impact on performance and underlying factors is still in its infancy. Here, we focus on the impact of interfaces, and nanostructure on fundamental processes which significantly contribute to performance in these organic photocatalysts. In particular, we focus on presenting explicit examples in understanding the interface of polymer photocatalysts with water and how it affects performance. Wetting has been shown to be a clear factor and we present strategies for increased wettability in conjugated polymer photocatalysts through modifications of the material. Furthermore, the limited exciton diffusion length in organic polymers has also been identified to affect the performance of these materials. Addressing this, we also discuss how increased internal and external surface areas increase the activity of organic polymer photocatalysts for hydrogen production from water.

In Situ Separator Modification with an N-Rich Conjugated Microporous Polymer for the Effective Suppression of Polysulfide Shuttle and Li Dendrite Growth

Lithium-sulfur (Li-S) batteries are very promising high-energy-density electrochemical energy storage devices, but suffer from serious Li polysulfide (LiPS) shuttle and uncontrollable Li dendrite growth. Here, we show in situ polyolefin separator modification with an N-rich conjugated microporous polymer (NCMP) for advanced Li-S battery. In situ polymerization generates an ultrathin NCMP coating on the whole external surface and the internal surface of the separator, which is substantially different from the conventional approaches with thick coatings only on the external surface. The NCMP coating with abundant N-containing groups (-NH₂ and -N═), uniform nanopores (12.294 Å), and π-conjugated structure can simultaneously inhibit LiPS shuttle and regulate uniform nucleation and growth of Li dendrites. Consequently, the NCMP-based separator endows the Li-S battery with significantly enhanced cycling stability at high S loading (5.4 mg cm^-2), lean electrolyte (E/S = 6.3 μL mg^-1), and limited Li excess (50 μm).

Processable Conjugated Microporous Polymer Gels and Monoliths: Fundamentals and Versatile Applications

Conjugated microporous polymers (CMPs) as a new type of conjugated polymers have attracted extensive attention in academia and industry because of the combination of microporous structure and π-electron conjugated structure. The construction and application of gels and monoliths based on CMPs constitute a fertile area of research, promising to provide solutions to complex environmental and energy issues. This review summarizes and objectively analyzes the latest advances in the construction and application of processable CMP gels and monoliths, linking the basic and enhanced properties to widespread applications. In this review, we open with a summary of the construction methods used to build CMP gels and monoliths and assess the feasibility of different preparation techniques and the advantages of the products. The CMP gels and monoliths with enhanced properties involving various special applications are then deliberated by highlighting relevant scientific literature and discussions. Finally, we present the issues and future of openness in the field, as well as come up with the major challenges hindering further development, to guide researchers in this field.

Application of Metal–Organic Framework in Diagnosis and Treatment of Diabetes

Diabetes-related chronic wounds are often accompanied by a poor wound-healing environment such as high glucose, recurrent infections, and inflammation, and standard wound treatments are fairly limited in their ability to heal these wounds. Metal–organic frameworks (MOFs) have been developed to improve therapeutic outcomes due to their ease of engineering, surface functionalization, and therapeutic properties. In this review, we summarize the different synthesis methods of MOFs and conduct a comprehensive review of the latest research progress of MOFs in the treatment of diabetes and its wounds. State-of-the-art in vivo oral hypoglycemic strategies and the in vitro diagnosis of diabetes are enumerated and different antimicrobial strategies (including physical contact, oxidative stress, photothermal, and related ions or ligands) and provascular strategies for the treatment of diabetic wounds are compared. It focuses on the connections and differences between different applications of MOFs as well as possible directions for improvement. Finally, the potential toxicity of MOFs is also an issue that we cannot ignore.

Recent Advancements in Microneedle Technology for Multifaceted Biomedical Applications

Microneedle (MNs) technology is a recent advancement in biomedical science across the globe. The current limitations of drug delivery, like poor absorption, low bioavailability, inadequate skin permeation, and poor biodistribution, can be overcome by MN-based drug delivery. Nanotechnology made significant changes in fabrication techniques for microneedles (MNs) and design shifted from conventional to novel, using various types of natural and synthetic materials and their combinations. Nowadays, MNs technology has gained popularity worldwide in biomedical research and drug delivery technology due to its multifaceted and broad-spectrum applications. This review broadly discusses MN’s types, fabrication methods, composition, characterization, applications, recent advancements, and global intellectual scenarios.

Bifunctional conjugated microporous polymer based filters for highly efficient PM and gaseous iodine capture

Cross-linked conjugated microporous polymers (CMPs) based air filters obtained by a one-step cross-coupling reaction for effective capture of particulate matter and gaseous iodine from dusty air.

Facile metal-free synthesis of pyrrolo[3,2-b]pyrrolyl-based conjugated microporous polymers for high-performance photocatalytic degradation of organic pollutants

An efficient and metal-free approach to the synthesis of new kinds of CMPs (pyrrolo[3,2-b]pyrrolyl-based CMPs) on a gram scale within a short time has been developed for remarkable adsorbent and photocatalytic degradation of organic pollutants.

Fully unsaturated all-carbon bifluorenylidene-based polymeric frameworks: synthesis and efficient photocatalysis

Conjugated porous polymers with fully unsaturated all-carbon frameworks possess strong visible light-absorbing abilities, enabling efficient photodegradation of dye pollutants.