Search

A facile synthesis strategy of multi-component functional synergy absorbers with a minimum reflection loss value (RLmin) of −51.74 dB at only 1.9 mm (11.12 GHz) and the efficient absorption bandwidth (EAB) of 4.28 GHz at 1.4 mm.

ROS-RAFT polymerization was conducted in aqueous system under open-to-air condition by using two imine COFs as photocatalysts. This work opens a novel pathway for RAFT polymerization application and expand the category of RAFT photocatalyst.

High-performance hydrogels with favorable mechanical strength, high modulus, sufficient ionic conductivity and freezing resistance have far-ranging applications in flexible electronic equipment. Nevertheless, it is challenging to combine admirable mechanical properties and high ionic conductivity into one hydrogel. Herein, a facile strategy was developed for the preparation of the hydrogel with excellent strength (1.45 MPa), super Young's modulus (8.85 MPa) and high conductivity (1.47 S/m) using starch and poly(vinyl alcohol) (PVA) as raw materials. The starch/PVA/Gly/Na

Conjugated microporous polymers (CMPs) are widely used as adsorbents due to their unique advantages, including microporous structure, large π-conjugated system, and structural stability. In this study, three types of CMP adsorbents (B-BTD-CMPs) containing different amounts of benzothiadiazole groups were obtained through Suzuki-Miyaura cross-coupling polycondensation reactions to investigate their performances in organic dye removal. The high charge density of nitrogen atoms in benzothiadiazole groups facilitates binding of small molecule dyes through a variety of non-covalent interactions. The results showed B-BTD-1,2,4,5, which containing the most benzothiadiazole groups, had the highest adsorption capacity of for rhodamine B (RhB) up to 531.20 mg g− 1. Furthermore, the adsorption performances of these CMPs on RhB under acidic, neutral, and basic conditions were almost identical, suggesting excellent acid and alkaline resistance. The adsorption capacity of CMPs decreased by less than 10% after five cycles, indicating excellent cyclic stability. It can be deduced that B-BTD-CMPs with stable structures and properties are excellent candidate adsorbents for dye wastewater treatment. This study also demonstrates that introducing N-containing functional groups into porous polymers is beneficial for the adsorption of small-molecule dyes, providing new design ideas for absorbents for dye wastewater treatment.

The synthesis of cyclic polymer is an important topic in polymer chemistry. Herein, we report a one-step method to prepare cyclic polypyrazoles. Monomers with two functional groups, diazo and alkyne, were synthesized and polymerized via 1,3-diploar cycloaddition in bulk under heating without any catalyst. Polypyrazoles with molecular weights in the range of 3800-4400 g/mol and yields in the range of 78.8-98.7% were successfully synthesized. No chain end group was detected by LC-QTOF-MS and FTIR, which proves the cyclic structure of polypyrazoles. What is noteworthy is that the cyclic polypyrazoles can self-assemble into vesicles during the reprecipitation process, which was proved by the results of SEM and TEM. The reason for that is the formation of intermolecular hydrogen bond between NH and ester groups.

We successfully synthesized a catalyst with a wide absorption range (300–1000 nm) for controlled radical polymerization of PEGMA in aqueous solution and MMA in bulk under the irradiation of white, blue, green, red, and NIR LED light, and sunlight.

An ionic heterogeneous catalyst, TD-I, was developed for the RCMP of PPEGMA in aqueous solution under white LED irradiation.

A reversible addition–fragmentation chain transfer (RAFT) polymerization system (COF/H2O/O2) using a heterogeneous photobionic enzyme (TFPPy-azine-COF) is proposed with water and oxygen as feedstocks.

The generation of cyclic carbonates by the cycloaddition of CO

Heteroatom doped porous carbon materials have great application prospects in supercapacitors. In the present study, an approach of preparing N-doped porous carbon (NPC) was proposed from porous poly(resorcinol-formaldehyde-melamine) monoliths which were prepared by high internal phase emulsion (HIPE) template. Melamine was dissolved in the external phase and copolymerized, acting as the N source and porous structure regulator to provide micropore-dominant NPCs. The structure, morphology, specific surface area (SSA), and chemical composition of the samples were systematically studied. With melamine content increasing, N-doping content in NPC increased while the SSA of NPC increased at first and then decreased. When the content of N is 8.42 ​wt%, the obtained NPC showed the highest SSA of about 1670 ​m2 ​g−1. Furthermore, high N doping content could improve the electronic conductivity and provide additional pseudocapacitance of NPC. Under the combined influences of proper N content and high porosity, the prepared NPC electrodes revealed excellent specific capacitance (228.0 ​F ​g−1 at 1.0 ​A ​g−1), favorable circling stability, and prominent rate capability in a three-electrode system with 6 ​M KOH solution as the electrolyte.

CoS

Two imine-based covalent organic framework photocatalysts with different building units, TPB-DMTA-COF and TAT-DMTA-COF, for photo-induced energy transfer reversible complexation-mediated radical polymerization (PET-RCMP) were developed and investigated, producing ideal polymers with accurate molecular weight and moderate dispersity under visible light irradiation. The chain extension and spatiotemporal control experiments revealed the high chain-end fidelity of polymers and the compatibility of RCMP processes in both bulk and aqueous system. Moreover, density functional theory (DFT) calculations verified that heteroatom-doped TAT-DMTA-COF exhibits higher activities for weakening C-I bond energy barrier, which promotes PET-RCMP polymerization performance. This work demonstrates that rational adjustment of building block for constructing COF heterogeneous photocatalyst can enhance the catalytic performance of PET-RCMP, providing a design methodology for the development of polymeric organic photoelectric semiconductor catalysts to mediate RCMP.

Rational design and controllable synthesis of multiple metal components according to chemical composition and morphology are essential for obtaining desirable electrochemical performance for efficient hydrogen production because of the morphology and synergistic effects of different components. Herein, we report an approach to facilely fabricate bimetal compounds with a well-defined hollow nanoprism structure using a self-templated strategy to synthesize novel hierarchical NiCo-layered double hydroxide (NiCo-LDH) nanosheets as precursors followed by in situ phosphorization. Among the as-synthesized products of different mole ratios of Ni/Co, the NiCo2-B-P nanoprisms that integrate the advantages of a hollow structure, an optimal Ni-Co synergistic effect, and a unique B-doped CoP/Ni2P bimetallic phosphide derived from NiCo-LDH nanosheets exhibit excellent hydrogen evolution reaction (HER) activity in an alkaline solution at 10 mA cm-2 with the lowest overpotential of 78 mV and long-term stability. This study may offer an appropriate structure and compositional design of bimetallic alkaline HER catalysts.

Photo-induced controlled radical polymerization (CRP) using heterogeneous catalysts offers excellent spatiotemporal control and has attracted special attention owing to its potential for green chemistry and biomedical applications. Herein, an imine-based conjugated microporous polymer material (EI-CMP) with high stability, recyclability and catalytic efficiency was synthesized under mild conditions. An alkyl radical (R˙) from alkyl iodide (R-I) with EI-CMP under white LED light was generated to initiate polymerization. Polymers with narrow molecular weight dispersity and controllable molecular weight can be produced by the polymerization of some functional methacrylates. Without photoirradiation, no polymerization occurs, suggesting that the polymerization is an ideal photo “on”–“off” switchable system. The high chain-end fidelity of iodine end-capped poly(methyl methacrylate) was confirmed by a chain-extension reaction. The catalytic ability of EI-CMP did not decrease after three cycles. An attractive feature of this method is the development of a heterogeneous photocatalyst which enables easy separation and efficient reusability.

An imine-based covalent organic framework, TFPPy-Td-COF, was synthesized to mediate photo-induced controlled radical polymerization (CRP) with copper under white light irradiation, providing polymethylacrylates with narrow molecular weight dispersity and high chain-end fidelity. This new methodology provides future directions for CRP using robust and heterogeneous COF-based catalysts under visible light conditions.

Conductive hydrogels have found large application prospects in the fabrication of flexible multifunctional electronic devices for future-generation wearable human–machine interactions. However, their inferior mechanical strength, low-temperature resistance, and non-recyclability, resulting in the waste of resources, severely hinder their application. Thus, starch bio-based hydrogels have attracted significant attention. Starch is the most abundantly available biodegradable biopolymer. However, starch bio-based hydrogels usually show low toughness, high brittleness and low anti-freezing properties. Thus, to address these issues, herein, glycerol and CaCl2 were concurrently introduced to a starch/poly(vinyl alcohol) (PVA) hydrogel to improve its mechanical, thermal and conductive properties. The effect of glycerol and CaCl2 on the crystallinity, mechanical, thermal and conductive properties was revealed by X-ray diffraction, tensile testing, differential scanning calorimetry, and electrochemical impedance spectroscopy. The thermoplasticity and healing properties of the starch/PVA/glycerol/CaCl2 organohydrogel was also evaluated. Due to the role of glycerol and CaCl2, the compatibility between starch and PVA improved, and thus the as-prepared organohydrogels showed favorable mechanical flexibility and demonstrated anti-freezing ability and long-term stability at ambient temperature. Besides, the abundant hydrogen bonds formed among PVA, starch, glycerol and water endowed the organohydrogels with high stretchability (>790%) and good thermoplasticity. Finally, based on the starch/PVA/glycerol/CaCl2 organohydrogel, a flexible all-solid-state supercapacitor and strain sensor were assembled and their performances were measured. The supercapacitor displayed an areal specific capacitance of 107.2 mF cm−2 at 1 mA cm−2. Moreover, the strain sensor demonstrated high sensitivity (gauge factor of 3.422) and could be directly attached to the human body to detect motion.

In this contribution, we propose a novel multipath aerobic-mediated reductive quenching pathway for a photoinduced electron transfer reversible addition fragmentation chain transfer polymerization process, where the in situ production of a superoxide anion radical from molecular oxygen was achieved under red light-emitting diode irradiation in the presence of a conjugated TCPP-DMTA-COP organic polymer with or without the assistance of triethylamine.

Hydrogels are important for stretchable and wearable multifunctional sensors, but their application is limited by their low mechanical strength and poor long-term stability. Herein, a conductive organohydrogel with a 3D honeycomb structure was prepared by integrating carbon nanotubes (CNTs) and carbon black (CB) into a poly(vinyl alcohol)/glycerol (PVA/Gly) organohydrogel. Such a nanocomposite organohydrogel is built on a physical cross-linking network formed by the hydrogen bonds among PVA, glycerol, and water. CNTs and CB had an add-in synergistic impact on the mechanical and electrical performances of the PVA/Gly organohydrogel because of the distinct aspect ratios and geometric shapes. The prepared organohydrogel integrated with a tensile strength of 4.8 MPa, a toughness of 15.93 MJ m-3, and flexibility with an elongation at break up to 640%. The organohydrogels also showed good antifreezing feature, long-term moisture retention, self-healing, and thermoplasticity. Sensors designed from these organohydrogels displayed high stretching sensitivity to tensile strain and temperature, with a gauge factor of 2.1 within a relatively broad strain range (up to ∼600% strain), a temperature coefficient of resistance of -0.935%·°C-1, and long-term durability. The sensors could detect full-range human physiological signals and respond to the change in temperature, which are highly desired for multifunctional wearable electronic devices.

Carbon-based materials are attractive in heterogeneous catalysis. In addition to be an ideal support for catalytic active species, carbon can form a protecting layer for non-noble metal nanoparticles (NPs) to prevent them from being oxidized. However, the synthesis of carbon supported non-noble metal NPs, with an even distribution of these transition metal NPs coated by a carbon shell, is still challenging. In this work, carbon supported metallic Co NPs coated by a graphitic carbon layer (C/Co@C) was successfully synthesized via calcinating of Co-MOF-74 at 1000 °C. The highly selective semi-hydrogenation of aromatic alkynes with NaBH4 to produce aromatic alkenes was realized over the as-obtained C/Co@C, in which the graphitic carbon layer acts like a “one-way valve” to allow BH4− to flow through, while preventing the larger size aromatic alkyne from entering the carbon shell to avoid its excessive hydrogenation. This work highlights the important role of using MOFs as precursor to prepare stable supported metal NPs for heterogeneous catalysis.

Biomass carbon materials which have the merits of green, low cost and renewability, can be obtained from sodium alginate (SA) beads crosslinked by polyvalent metal ions. SA beads are possible to be obtained using diammoniums as the crosslinking agents. In this work, N-O codoped porous carbon (NO-PC) was prepared from SA beads crosslinked by diammoniums through the electrostatic interaction between ammonium cations and carboxylate groups of SA chains. The using of diammoniums as the crosslinkers achieved N doping into NO-PC. Scanning and transmission electron microscope observations revealed that NO-PC possessed hierarchically porous characteristic. X-ray photoelectron spectroscopy identified the successful N-O codoping. Both the species and concentration of diammoniums strongly affected the porous structure, surface area and electrochemical performance of NO-PC. N2 adsorption-desorption results of NO-PC indicated that the highest surface area was up to 3794 m2/g. The NO-PC based supercapacitors showed high specific capacities up to 269.0 F/g at 1 A/g and excellent cycling stability (92.09% after 5000 cycles at 5 A/g). The energy density of the symmetric supercapacitor was up to 18.9 Wh/kg at a power density of 1380 W/kg with a voltage window of −1.4–0 V.

It is well-known that tissue engineering scaffolds that feature highly interconnected and size-adjustable micropores are oftentimes desired to promote cellular viability, motility, and functions. Unfortunately, the ability of precise control over the microporous structures within bioinks in a cytocompatible manner for applications in 3D bioprinting is generally lacking, until a method of micropore-forming bioink based on gelatin methacryloyl (GelMA) was reported recently. This bioink took advantage of the unique aqueous two-phase emulsion (ATPE) system, where poly(ethylene oxide) (PEO) droplets are utilized as the porogen. Considering the limitations associated with this very initial demonstration, this article has furthered the understanding of the micropore-forming GelMA bioinks by conducting a systematic investigation into the additional GelMA types (porcine and fish, different methacryloyl-modification degrees) and porogen types (PEO, poly(vinyl alcohol), and dextran), as well as the effects of the porogen concentrations and molecular weights on the properties of the GelMA-based ATPE bioink system. This article exemplifies not only the significantly wider range of micropore sizes achievable and better emulsion stability, but also the improved suitability for both extrusion and digital light processing bioprinting with favorable cellular responses.

In this paper, quaternary ammonium salt type Gemini surfactant G12 was designed and synthesized, and its structure was characterized by infrared and nuclear magnetic resonance. The surface tension, permeability, emulsification ability and cleaning of insulator surface contamination in the composite system were tested, and the test results showed that it had low critical micelle concentration (cmc) and good emulsification performance. Due to the presence of rigid groups, the permeability is average. When quaternary ammonium Gemini surfactant G12 is mixed with permeant JFC-E, and is combined with auxiliary and organic solvent, the cleaning rate of insulators can reach more than 90%.

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose‐limiting toxicity remain as major dilemmas for immunotherapy. Stimuli‐responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti‐tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti‐tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long‐term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

The work reported the preparation of hierarchically porous carbons (HPCs) with adjustable pore architectures using high internal phase emulsion (HIPE) template with the presence of polyaniline-coated carbon nanotubes (PANI-CNTs). PANI-CNTs were obtained via in situ polymerization of aniline in CNT suspension as confirmed by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). Porous polydivinylbenzene (PDVB) monoliths were prepared by polymerizing the continuous phase of HIPE with PANI-CNTs dispersed in the internal phase. After carbonization and activation, HPCs with variable pore architectures were obtained. As observed by SEM, the PANI-CNTs showed notable influence on the pore architectures of PDVBs and HPCs. The void size of PDVB precursor reduced with the increase of the mass ratio of PANI to CNT, as well as the content of PANI-CNTs. Nitrogen adsorption/desorption measurements indicated the coexistence of mesopores and micropores, namely, hierarchical pores. The specific surface area (SSA) of HPC increased along with the content of PANI-CNTs from 1893 to 2392 m2/g. The capability of HPCs as the electrode material of supercapacitor was evaluated via electrochemical tests. The results indicated that the HPC with optimized pore architecture showed a higher specific capacitance (168.6 F/g) than the contrast sample (130.9 F/g) at 1 A/g. The better capacitance performance of HPC obtained with the presence of PANI-CNTs could be attributed to the reasonable hierarchical pores, higher SSA, and higher graphitization degree.

Heterostructures with multiple electrocatalytically active components to simultaneously satisfy electrochemical and structural requirements have recently been regarded as materials with high catalytic activity in the hydrogen evolution reaction (HER). Herein, hybrid structures of CoS2/SnO2@MoS2 (CSM1) nanocubes are synthesized via a fast template-engaged hydrothermal treatment employing perovskite hydroxide CoSn(OH)6 nanocubes as precursor templates. The self-template strategy has the ability to construct samples with a multicomponent structure, including highly catalytically active components of CoS2 and MoS2 as well as highly conductive SnO2, with a porous interior. Benefiting from the merits of appropriate composition and well-retained porous nanocube structure, the CSM1 nanocubes exhibit the HER performance with a desired overpotential of 196 mV at a current density of 10 mA cm−2, a small Tafel slope of 69 mV dec−1 and long-time stability in acidic media. This protocol sheds light on designing a rational structure with prominent electrocatalytic activity and stability in energy-related applications.