Introducing Polar Groups in Porous Aromatic Framework for Achieving High Capacity of Organic Molecules and Enhanced Self-Cleaning Applications.

Due to the frequent oil/organic solvent leakage, efficient oil/water separation has attracted extensive concern. However, conventional porous materials possess nonpolar building units, which reveal relatively weak affinity for polar organic molecules. Here, two different polarities of superhydrophobic porous aromatic frameworks (PAFs) were synthesized with respective orthoposition and paraposition C=O groups in the PAF linkers. The conjugated structure formed by a large number of alkynyl and benzene ring structures enabled porous and superhydrophobic quality of PAFs. After the successful preparation of the PAF solids, PAF powders were coated on polyester fabrics by a simple dip-coating method, which endowed the resulting polyester fabrics with superhydrophobicity, porosity, and excellent stability. Based on the unique structure, the oil/water separation efficiency of two superhydrophobic flexible fabrics was more than 90% for various organic solvents. Polar LNU-26 PAF showed better separation performance for the polar oils. This work takes the lead in adopting the polar groups as building units for the preparation of porous networks, which has great guiding significance for the construction of advanced oil/water separation materials.

Integrating a Luminescent Porous Aromatic Framework into Indicator Papers for Facile, Rapid, and Selective Detection of Nitro Compounds.

Porous aromatic framework materials with high stability, sensitivity, and selectivity have great potential to provide new sensors for optoelectronic/fluorescent probe devices. In this work, a luminescent porous aromatic framework material (LNU-23) was synthesized via the palladium-catalyzed Suzuki cross-coupling reaction of tetrabromopyrene and 1,2-bisphenyldiborate pinacol ester. The resulting PAF solid exhibited strong fluorescence emission with a quantum yield of 18.31%, showing excellent light and heat stability. Because the lowest unoccupied molecular orbital (LUMO) of LNU-23 was higher than that of the nitro compounds, there was an energy transfer from the excited LNU-23 to the analyte, leading to the selective fluorescence quenching with a limit of detection (LOD) ≈ 1.47 × 10-5 M. After integrating the luminescent PAF powder on the paper by a simple dipping method, the indicator papers revealed a fast fluorescence response to gaseous nitrobenzene within 10 s, which shows great potential in outdoor fluorescence detection of nitro compounds.

An Azo-Group-Functionalized Porous Aromatic Framework for Achieving Highly Efficient Capture of Iodine.

The strong radioactivity of iodine compounds derived from nuclear power plant wastes has motivated the development of highly efficient adsorbents. Porous aromatic frameworks (PAFs) have attracted much attention due to their low density and diverse structure. In this work, an azo group containing PAF solid, denoted as LNU-58, was prepared through Suzuki polymerization of tris-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl)-amine and 3,5-dibromoazobenzene building monomers. Based on the specific polarity properities of the azo groups, the electron-rich aromatic fragments in the hierarchical architecture efficiently capture iodine molecules with an adsorption capacity of 3533.11 mg g-1 (353 wt%) for gaseous iodine and 903.6 mg g-1 (90 wt%) for dissolved iodine. The iodine uptake per specific surface area up to 8.55 wt% m-2 g-1 achieves the highest level among all porous adsorbents. This work illustrates the successful preparation of a new type of porous adsorbent that is expected to be applied in the field of practical iodine adsorption.

Dimensionality Control of 1D Coupling Reaction for the Facile Preparation of Porous Carbon Nanofibers.

Porous carbon nanofibers with unique hierarchical structures have great potential in many fields, including heterogeneous catalysis, optoelectronics, and sensing. However, several preparation issues, such as additional templates, complicated processes, and harsh conditions, seriously hamper their widespread use. Here, we control the Sonogashira coupling reaction of linear building monomers─1,4-dibromaphthalene and 1,4-ethylbenzene─at the molecular level. Due to the occurrence of branching chain reaction (side reaction), 1D oligomer expands the growth orientation in the plane direction, forming a curled 1D fiber polymer. After thermal-driven skeleton engineering, porous carbon nanofibers were obtained with hierarchical channels of macro- (150 nm), meso- (5.2 nm), and microcavities (0.5 and 1.3 nm). The integration of macro-/meso-/microporous structure reveals a fast and sufficient interaction with electrolyte molecules, facilitating the construction of high-performance electrical devices. Our strategy, using a side reaction to achieve the dimensionality control of 1D copolymerization, paves a new way for the facile preparation of porous carbon nanofibers.

A Carbazole-Functionalized Porous Aromatic Framework for Enhancing Volatile Iodine Capture via Lewis Electron Pairing.

Nitrogen-rich porous networks with additional polarity and basicity may serve as effective adsorbents for the Lewis electron pairing of iodine molecules. Herein a carbazole-functionalized porous aromatic framework (PAF) was synthesized through a Sonogashira-Hagihara cross-coupling polymerization of 1,3,5-triethynylbenzene and 2,7-dibromocarbazole building monomers. The resulting solid with a high nitrogen content incorporated the Lewis electron pairing effect into a π-conjugated nano-cavity, leading to an ultrahigh binding capability for iodine molecules. The iodine uptake per specific surface area was ~8 mg m-2 which achieved the highest level among all reported I2 adsorbents, surpassing that of the pure biphenyl-based PAF sample by ca. 30 times. Our study illustrated a new possibility for introducing electron-rich building units into the design and synthesis of porous adsorbents for effective capture and removal of volatile iodine from nuclear waste and leakage.

Pyrene-Based Fluorescent Porous Organic Polymers for Recognition and Detection of Pesticides.

Eating vegetables with pesticide residues over a long period of time causes serious adverse effects on the human body, such as acute poisoning, chronic poisoning, and endocrine system interference. To achieve the goal of a healthy society, it is an urgent issue to find a simple and effective method to detect organic pesticides. In this work, two fluorescent porous organic polymers, LNU-45 and LNU-47 (abbreviation for Liaoning University), were prepared using π-conjugated dibromopyrene monomer and boronic acid compounds as building units through a Suzuki coupling reaction. Due to the large π-electron delocalization effect, the resulting polymers revealed enhanced fluorescence performance. Significantly, in sharp contrast with the planar π-conjugated polymer framework (LNU-47), the distorted conjugated structure (LNU-45) shows a higher specific surface area and provides a broad interface for analyte interaction, which is helpful to achieve rapid response and detection sensitivity. LNU-45 exhibits strong fluorescence emission at 469 nm after excitation at 365 nm in THF solution, providing strong evidence for its suitability as a luminescent chemosensor for organic pesticides. The fluorescence quenching coefficients of LNU-45 for trifluralin and dicloran were 5710 and 12,000 (LNU-47 sample by ca. 1.98 and 3.38 times), respectively. Therefore, LNU-45 serves as an effective "real-time" sensor for the detection of trifluralin and dicloran with high sensitivity and selectivity.

Highly Efficient Enrichment of Volatile Iodine by Charged Porous Aromatic Frameworks with Three Sorption Sites.

The targeted synthesis of a series of novel charged porous aromatic frameworks (PAFs) is reported. The compounds PAF-23, PAF-24, and PAF-25 are built up by a tetrahedral building unit, lithium tetrakis(4-iodophenyl)borate (LTIPB), and different alkyne monomers as linkers by a Sonogashira-Hagihara coupling reaction. They possess excellent adsorption properties to organic molecules owing to their "breathing" dynamic frameworks. As these PAF materials assemble three effective sorption sites, namely the ion bond, phenyl ring, and triple bond together, they exhibit high affinity and capacity for iodine molecules. To the best of our knowledge, these PAF materials give the highest adsorption values among all porous materials (zeolites, metal-organic frameworks, and porous organic frameworks) reported to date.

A Single-Component Janus Zwitterionic Hydrogel Patch with a Bionic Microstructure for Postoperative Adhesion Prevention.

The development of anti-adhesion hydrogels for preventing postoperative adhesions is an ongoing challenge, particularly in achieving a balance between exceptional antifouling properties and effective in situ tissue retention. In this study, we propose a unique approach with the design of a single-component Janus zwitterionic hydrogel patch featuring a bionic microstructure. The Janus patches were prepared through free radical polymerization of sulfobetaine methacrylate with N, N'-methylenebis(2-propenamide) as the cross-linker. The incorporation of hexagonal facets separated by interconnecting grooves on one side imparts durable and reliable in situ retention capabilities to the Janus hydrogel patch when it is applied to traumatized tissues. The opposing flat surface exhibits outstanding resistance to bacteria, proteins, and cell adhesion, due to the superhydrophilicity and excellent antifouling characteristics of zwitterionic polymers. This dual functionality empowers the Janus hydrogel patch to mitigate adhesions between traumatized and surrounding tissues. The hexagonal and groove bionic microstructures facilitate rapid drainage, promoting swift contact with the tissue for increased adhesion strength, while independent hexagonal microfacets enhance the peeling energy. In an in vivo setting, Janus zwitterionic hydrogel patches with surface microstructures form mutually embedded structures with the cecum surface, minimizing the likelihood of slippage and detachment. Remarkably, in vivo experiments involving abdominal wall cecum injuries illustrate the Janus zwitterionic hydrogel patch's superior anti-adhesion effectiveness compared to commercial controls. Thus, the Janus hydrogel patch, distinguished by its bionic microstructure surface, presents substantial potential in the biomedical field for averting postoperative adhesions.

Mechanical-Enhanced and Durable Zwitterionic Hydrogel Coating for Inhibiting Coagulation and Reducing Bacterial Infection.

Blood-contact medical devices are indispensable for clinical interventions, yet their susceptibility to thrombosis and bacterial infections poses substantial risks to treatment efficacy and patient well-being. This study introduces a polysulfobetaine/alginate-CuII (SAC) zwitterionic hydrogel coating on polyurethane (PU) surfaces. This approach retains the superhydrophilic and antifouling nature of pSBMA while conferring the antibacterial effects of copper ions. Meanwhile, the copper alginate network intertwines with the polysulfobetaine (pSBMA) network, enhancing its mechanical properties and overcoming inherent weaknesses, thereby improving coating durability. Compared to the substrate, the SAC hydrogel coating significantly reduces thrombus adhesion mass by approximately 81.5% during extracorporeal blood circulation and effectively prevents bacterial biofilm formation even in a high-concentration bacterial milieu over 30 days. Moreover, the results from an isolated blood circulation model in New Zealand white rabbits affirm the impressive anticoagulant efficacy of the SAC hydrogel coating. The findings suggest that this hydrogel coating and its application method hold promise as a solution for blood-contact material surface modification to address thrombosis and bacterial biofilm formation simultaneously.

Strongly adhesive zwitterionic composite hydrogel paints for surgical sutures and blood-contacting devices.

Hydrogels show eminent advantages in biomedical and pharmaceutical fields. However, their application as coating materials for biomedical devices is limited by several key challenges, such as lack of universality, weak mechanical strength, and low adhesion to the substrate. Here we report versatile and tough adhesion composite hydrogel paints (CHPs), which consist of zwitterionic copolymers and microgels, both with reactive groups. The CHPs exhibit tunable rheology and thickness, hydrophilicity, biofouling resistance, durability, and convenient fabrication on metal, polymer, and inorganic surfaces with arbitrary shapes. As a proof-of-concept, the CHP-surgical sutures demonstrate exceptional lubrication, drug delivery, anti-infection, and anti-fibrous capsule properties. Moreover, the CHP-PVC tubing effectively prevents thrombus formation in vitro and ex vivo rabbit blood circulation without anticoagulants. This work provides valuable insights for enhancing and developing integrated hydrogel technologies for biomedical devices. STATEMENT OF SIGNIFICANCE: The combination of hydrogel and biomedical devices can enable numerous existing applications in medicine. In this study, inspired by the principle of microgel reinforcement in industrial paints, we propose a simple and versatile zwitterionic composite hydrogel paints (CHPs) strategy, which can be easily applied to diverse substrates with arbitrary shapes by covalent grafting between complementary groups by brush, dip, or spray. The CHPs integrated universality, tough adhesion, mechanical durability, and anti-biofouling properties because of their unique chemical composition and coating structure design. This strategy provides a simple and versatile route for surface modification of biomedical devices.

Bioinspired zwitterionic microgel-based coating: Controllable microstructure, high stability, and anticoagulant properties.

Zwitterionic polymers have shown promising results in non-fouling and preventing thrombosis. However, the lack of controlled surface coverage hinders their application for biomedical devices. Inspired by the natural biological surfaces, a facile zwitterionic microgel-based coating strategy is developed by the co-deposition of poly (sulfobetaine methacrylate-co-2-aminoethyl methacrylate) microgel (SAM), polydopamine (PDA), and sulfobetaine-modified polyethyleneimine (PES). The SAMs were used to construct controllable morphology by using the PDA combined with PES (PDAS) as the intermediate layer, which can be easily modulated via adjusting the crosslinking degree and contents of SAMs. The obtained SAM/PDAS coatings exhibit high anti-protein adhesive properties and can effectively inhibit the adhesion of cells, bacteria, and platelet through the synergy of high deposition density and controllable morphology. In addition, the stability of SAM/PDAS coating is improved owing to the anchoring effects of PDAS to substrate and SAMs. Importantly, the ex vivo blood circulation test in rabbits suggests that the SAM/PDAS coating can effectively decrease thrombosis without anticoagulants. This study provides a versatile coating method to address the integration of zwitterionic microgel-based coatings with high deposition density and controllable morphology onto various substrates for wide biomedical device applications. STATEMENT OF SIGNIFICANCE: Thrombosis is a major cause of medical device implantation failure, which results in significant morbidity and mortality. In this study, inspired by natural biological surfaces (fish skin and vascular endothelial layer) and the anchoring ability of mussels, we report a convenient and efficient method to firmly anchor zwitterionic microgels using an oxidative co-deposition strategy. The prepared coating has excellent antifouling and antithrombotic properties through the synergistic effect of physical morphology and chemical composition. This biomimetic surface engineering strategy is expected to provide new insights into the clinical problems of blood-contacting devices related to thrombosis.

Microgel reinforced zwitterionic hydrogel coating for blood-contacting biomedical devices.

Zwitterionic hydrogels exhibit eminent nonfouling and hemocompatibility. Several key challenges hinder their application as coating materials for blood-contacting biomedical devices, including weak mechanical strength and low adhesion to the substrate. Here, we report a poly(carboxybetaine) microgel reinforced poly(sulfobetaine) (pCBM/pSB) pure zwitterionic hydrogel with excellent mechanical robustness and anti-swelling properties. The pCBM/pSB hydrogel coating was bonded to the PVC substrate via the entanglement network between the pSB and PVC chain. Moreover, the pCBM/pSB hydrogel coating can maintain favorable stability even after 21 d PBS shearing, 0.5 h strong water flushing, 1000 underwater bends, and 100 sandpaper abrasions. Notably, the pCBM/pSB hydrogel coated PVC tubing can not only mitigate the foreign body response but also prevent thrombus formation ex vivo in rats and rabbits blood circulation without anticoagulants. This work provides new insights to guide the design of pure zwitterionic hydrogel coatings for biomedical devices.

Fine-regulating ultramicropores in porous carbon via a self-sacrificial template route for high-performance supercapacitors.

Ultramicropores (size < 0.7 nm) are critically demanded to provide an efficient path for the penetration and transportation of electrolytes to achieve high-performance supercapacitors. Here, a self-sacrificial template approach is adopted, which introduces C8 alkyl chains with a kinetic diameter of 0.8-1 nm to occupy the cavity of a porous aromatic framework (PAF). During the heating process, the alkyl chains decompose from the dense architecture as the temperature increased from 500 to 600 °C, forming ∼1 nm micropores. The newly-obtained cavities provide sites for thermal-driven skeleton engineering (700-900 °C) to obtain ultramicropores. Based on the well-defined pore structure, the carbonized PAF solid revealed outstanding electrochemical performances, including high rate and long-term stability in a 6 M KOH electrolyte. Notably, the specific capacitance (294 F g-1) derived from the self-sacrificial template method exceeds the capability of all the other methods for the construction of ultramicropores including self-template strategy, carbonization of nanoparticles, and template-assisted strategy. The synthesis of ultramicroporous carbons via the self-sacrificial template route opens up a promising gate to adjust the porous structure for high-performance applications in supercapacitors.

Preparation of mesoporous silica nanoribbons and nanoflakes with short pore channels using a chiral amphiphile.

A chiral cationic low-molecular-weight amphiphile, derived from L-alanine, was synthesized. Templated by the self-assemblies of the amphiphile, sol-gel reactions were carried out to control the morphologies and pore architectures of mesoporous silicas. The results reveal that the morphologies and pore architectures of mesoporous silicas are sensitive to the reaction conditions, such as temperature and the concentration of NaOH. When the reaction was carried out at 25 degrees C, righthanded coiled mesoporous silica nanoribbons with short pore channels were formed, most of which coiled tightly to form nanorods. However, at 80 degrees C, mesoporous silica nanoflakes with vertical pore channels were obtained.

Constructing "breathing" dynamic skeletons with extra π-conjugated adsorption sites for iodine capture.

Radioiodine (129I and 131I) emission from the nuclear waste stream has aroused enormous apprehension because of its quick diffusion and radiological contamination. Conventional porous adsorbents such as zeolites and carbon with rigid skeletons and constant pore volumes reveal a limited performance for reliable storage. Here, a series of soft porous aromatic frameworks (PAFs) with additional π-conjugated fragments is disclosed to serve as physicochemical stable media. Due to the flexibility of the tertiary amine center, the PAF products provide sufficient space for the binding sites, and thus exhibit a considerable capability for iodine capture from both gaseous and soluble environments. The obtained capacity of PAFs is ca. 1.6 times higher than that of PAF-1 which possesses similar aromatic constituents featuring an ultra-large specific surface area (BET = 5600 m2 g-1). The novel paradigm of dynamic frameworks is of fundamental importance for designing adsorbents to treat environmental pollution issues.

Influences of bioapatite mineral and fibril structure on the mechanical properties of chicken bone during the laying period.

Laying hens suffer from osteoporosis during their laying period, which causes bone fragility and susceptibility to fracture. This study evaluated the changes of mechanical properties of their bones during the laying period (from 18 to 77 wk) by using nano-indentation, atomic force microscope, X-Ray diffraction, and Raman spectroscopy. Results indicated that the crystallite sizes of bioapatite in femur decreased significantly from 34.45 to 29.26 nm during aging from 18 to 49 wk. Then, the value increased to 37.79 nm at 77 wk. Despite the abundance in bone (usually >50 wt.%), bioapatite mineral content showed no continuous enhancement during aging. The fibrils demonstrated more regular and organized structure during the laying period. Meanwhile the elastic moduli (E) and hardness (H) of femur increased from 10.84 to 18.39 GPa and 43.79 to 97.21 Vickers respectively during this period. The changes in mechanical properties are hence tightly related to the structure of bone (composed of both collagen and mineral), rather than directly related to the mineralogical properties of bone bioapatite. This study addressed the importance of the interaction between collagen and bioapatite mineral during the laying period of hens by microscopic, physicochemical, and mechanical analysis.

Facile formation of mesoporous structured mixed-phase (anatase/rutile) TiO2 with enhanced visible light photocatalytic activity.

A new mixed-phase (anatase/rutile) TiO2 with mesoporous structures and smaller crystal size (3-5 nm) was successfully synthesized by a facile sol-gel method at a lower calcination temperature (100 °C). Rhodamine B can be completely decomposed in the presence of the as-synthesized nanocomposite after only 60 minutes under visible light. Therefore it is believed to be a promising candidate for wastewater treatment.

A 3D microporous covalent organic framework with exceedingly high C3H8/CH4 and C2 hydrocarbon/CH4 selectivity.

Here we present a new 3D microporous COF with a uniform pore size (0.64 nm). MCOF-1 exhibits high adsorption selectivity towards C3H8, C2H6 and C2H4 over CH4 owing to the pore size and preferential adsorption.

Artificial frustule prepared through a single-templating approach.

An "artificial frustule" was prepared through a single-templating approach, where the self-assembled architecture undergoes a transition from cocoons with pore channels parallel to the surface, to hollow spheres with perpendicular pore channels.