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The maturity group (MG) system is widely used to group soybean [Glycine max (L.) Merr.] varieties based on their growth periods and photothermal responses. However, there is still no universal standard or quantifiable methodology for MG classification. In this study, phenological traits of 107 Chinese, 4 Far East Russian representative soybean varieties, and 113 North American reference varieties covering 13 MGs were evaluated at eight locations (ranging from 30 to 50° N) in four ecoregions of China for two consecutive years (2014 and 2015). Relative maturity groups (RMGs) were attributed to all the varieties based on the linear regression models. To decimalize the RMG values of the early-maturing varieties belonging to MGs below 0, negative values were defined for MGs 00, 000, and 0000. The additive main effects and multiplicative interaction (AMMI) model was used to screen 185 standard candidate varieties for MGs 0000 to VIII. This study provided a systematic and quantifiable methodology for RMG identification in soybeans. The methodology is expected to be widely adopted by soybean regionalization and germplasm exchanges throughout the world and will be helpful for characterizing the photothermal sensitivity and adaptability of the given soybean varieties.

A multisite-binding fluorescence turn-on probe of Rh6G NH PBA has been prepared in this study. The probe selectively responds to mitochondrion adenosine triphosphate (ATP) concentrations. The fluorescence intensity of Rh6G NH PBA toward ATP was enhanced by approximately 51-fold in water at 1.0 mM. In particular, Rh6G NH PBA exhibited good selectivity to ATP, surpassing other anions due to a cooperative effect from multisite-binding recognition. Live-cell imaging indicates that Rh6G NH PBA locates mainly into mitochondria with good biocompatibility. The results demonstrate that Rh6G NH PBA is a useful probe for the monitoring of mitochondria ATP-relevant processes.

Currently, the treatment and care of diabetic wounds, which generally possess the characteristics of a high amputation rate, high recurrence rate and high mortality, has developed into a worldwide challenge. Wound dressings have been playing an important role in diabetic wound treatment and continuously innovated to obtain many amazing properties. Among them, hydrogel dressings have become one of the most attractive and promising wound dressings because of their considerable moisture retention, biocompatibility and therapeutic properties. In recent years, with the in depth understanding of the pathogenesis of diabetic wounds, various functionalized hydrogel dressings have been reported and shown encouraging results, which has brought great benefits to the improvement of diabetic wounds. In this work, we will systematically and comprehensively summarize the advances of hydrogel dressings in diabetic wounds, aiming to provide not only theoretical support for hydrogel dressing devising but also inspiration for diabetic wound treatment.

In the present work, we developed a type of novel hyperbranched polymeric ionic liquid (HBPIL) that was derived from 1-allyl-3-methylimidazolium (AMIM), 1-allyl-3-methylpyridinium (AMPy), or 1-allyl-1-methylpiperidinium (AMPIP) cation with different anions, tetrafluoroborate (BF4), bis (trifluoromethylsulfonyl) amide (NTF2), and hexafluorophosphate (PF6), to elucidate the role of cations and anions on the reactivity and mechanical properties. The blending of HBPILs with bisphenol-F-based benzoxazines decreased the temperature required for opening the rings of the benzoxazines and improved the mechanical performances and thermal behaviors of the formed polybenzoxazoles. Moreover, differential scanning calorimetry, TGA, and Fourier transform infrared data exhibited the following differences: (i) the curing process was correlated to the structural differences of the anions, and the onset temperature was lower for the HBPIL with the PF6 anion in comparison to those with the NTF2 and BF4 anions; (ii) the type of cation had a significant influence on the curing reactivity of the benzoxazines, with the highest catalytic activity observed for the HBPIL containing AMIM, compared to those with (AMPy) and (AMPIP). Furthermore, the higher catalytic activity of the HBPILs for the benzoxazines suggested a higher crosslink density of the cured resin, which enabled the glass transition temperature to shift to a higher value and enhanced the mechanical strength and thermal stability of the obtained polybenzoxazoles.

Epoxy-ended hyperbranched polymers (EHPs), as important type of functional thermosetting hyperbranched polymers, have attracted broad and continuing interest from both academic and industrial researchers. Benefiting from their high-crosslinking ability, void-containing topological structure and very low viscosity, EHPs have been widely applied in reinforcing and toughening diglycidyl ether of bisphenol-A (DGEBA) and in solvent-free or environmentally-friendly coatings. Therefore, the design and synthesis of EHPs provide a robust tool for controlling the interfacial interaction between EHPs and DGEBA to finally gain excellent comprehensive performance. In this review, the perspectives and recent advances of preparation methods, performance control and promising applications of various EHPs have been comprehensively summarized. In addition, a single toughening function, a simultaneously reinforcing and toughening function and the mechanism of DGEBA by EHPs are also discussed and investigated by integrating molecular simulations, dynamic mechanical analysis (DMA) and scanning electron microscope (SEM) technologies. EHPs with high contents of epoxy group show simultaneous reinforcing and toughening in DGEBA, regardless of their aliphatic and aromatic structures, and whether there is phase-separation or homogenous structure associated with the fractured surface. The simultaneous reinforcing and toughening mechanism changes the conventional conception of inter-contradiction between the toughening and reinforcing function. It was also found that EHPs with different synthetic strategies and diverse performance have allowed an increasing number of versatile industrial applications.

Although nucleophile (Nu) is associated with many important chemical reactions, there are no fluorescence sensors for Nu detection and even for calculation of its nucleophilicity up to the present. In this study, we developed a fluorescent malononitrile-modified perylenediimide (MAPDI) which can selectively and rapidly react with nucleophiles, such as amines, amino acids, and some inorganic anions, and then change its UV-vis absorption and fluorescence emission. Detection limits of MAPDI for different nucleophiles could be calculated to compare their strength of nucleophilicity. Furthermore, it was found that MAPDI could detect reductive inorganic anions. These results suggested that MAPDI might have a great potential in organocatalytic reactions, metal ion-catalyzed reactions, reactions of amines, and other nucleophilic chemical reactions.

The development of biocompatible vector for hydrophobic drug delivery remains a longstanding issue in cancer therapy. We design and synthesis a drug delivery system based on HPG modified β-CD (β-CD-HPG) by conjugating HPG branches onto β-CD core and its structure was confirmed by NMR, FTIR, GPC and solubility. In vitro biocompatibility tests showed that HPG modification significantly improved red blood cells morphology alteration and hemolysis cause by β-CD and β-CD-HPG displayed cell safety apparently in a wide range of 0.01–1 mg/mL. An anti-cancer drug, docetaxel, was effectively encapsulated into β-CD-HPG which was confirmed by DSC analysis. This copolymer could form nanoparticles with small size (< 200 nm) and exhibited better DTX loading capacity and controlled release kinetics without initial burst release behavior compared with β-CD. Furthermore, antitumor assay in vitro show that β-CD-HPG/DTX effectively inhibited proliferation of human breast adenocarcinoma cells. Therefore, β-CD-HPG/DTX exhibit great potential for cancer chemotherapy.

G4 PAMAM dendrimer molecules were modified via covalently conjugating RGDC, RAADyC, and PEG chains on the periphery (Mac-1), by which a nanogel drug carrier with enzyme-sensitivity (NG-1) was constructed through an oxidation reaction by using NaIO4 to initiate the chemical cross-link of the functional groups on the periphery of dendrimers. Mac-1 and NG-1 both had a spherelike shape with a relatively uniform size of 20 nm for Mac-1 and 50 nm for NG-1 as evidenced by TEM, SEM, and DLS measurements. NG-1 showed much higher drug loading capacity as compared with that of Mac-1 although the cavities in the dendritic structure were used to encapsulate drug molecules as reported in many literatures. In addition, the size of NG-1 with embedded doxorubicin hydrochloride (DOX) decreased significantly to 15 nm in the presence of elastase, which indicated the decomposition of the nanogel triggered by enzyme, leading to drug release in a sustained manner in vitro. The NG-1 carrier was noncytotoxic and biocompatible, and it achieved the same cytotoxicity as free DOX when the drug molecules were loaded inside. From confocal images, the penetrative process of DOX from nanogel could be clearly observed in 8 h. Such a dendrimer-based nanogel may be a potential nanocarrier for drug delivery in cancer therapy.

A challenge to polymer scientists is to design new materials with superior overall performance in heat-resistance, cold-resistance, strength, and toughness. Here we report the synthesis of hyperbranched polymers containing epoxy and imide structure (EHPI-n, n = 6, 12, and 24) with various molecular weights and degrees of branching using a new synthetic diimide dicarboxylic acid. EHPI-n significantly decreases the gelation time and accelerates the curing of EHPI-n/diglycidyl ether of bisphenol-A (DGEBA). Both EHPI-6 and EHPI-12 significantly reduce the viscosity, activation energy, and average particle size of EHPI-n/DGEBA blends due to the disentangling function and compatibility of the EHPI-n. The toughness property, including elongation at break, impact strength, critical strain energy value (GIC) and critical stress intensity factor (KIC) of 12 wt % EHPI-12/DGEBA composites are improved over the neat DGEBA, by 144.72 %, 197.9 %, 168.4 % and 72.6 %, respectively, while their mechanical properties, including tensile strength, storage modulus and flexural strength are enhanced by 61.2 %, 89.9 %, 44.2 %. The heat-resistant index and β-relaxation peak temperatures of the composites are improved 14 °C and 15 °C, respectively, indicating both outstanding high-temperature resistance and outstanding low-temperature resistance. The simultaneous improvement on multiple performances is attributable to an in-situ homogeneous reinforcing and toughening mechanism, which is explained by free volume fraction, microstructure and surface micrograph. The EHPI-n present great potential as advanced materials for aerospace and wind turbine.

Cu2+ is an eminent trace metal ion in the human body as a structural cofactor that can enhance immune function. Aluminum is one of the most abundant elements found in the earth's crust and most biological tissues appear in Al3+ form. Hg2+ is probable to cause cancer with high toxicity. However, excess accumulation of Al3+, Cu2+ or Hg2+ in the body leads to many diseases. Therefore, detecting the level of Al3+, Cu2+ and Hg2+ are very important for human health. However, preparing a suitable single probe for the simultaneous detection of Al3+, Cu2+ and Hg2+ remains a challenge. TPE-based carbohydrazide derivative (TPE-Ch) was synthesized by the one-pot reaction. The TPE-Ch displayed notable AIE and AIEE phenomena and can act as a fluorescence sensor that turns on toward Al3+ in ethanol/water mixtures (fw = 70%) and turns off toward Cu2+ or Hg2+. TPE-Ch can produce various assemblies by coordination with Al3+, Cu2+ and Hg2+, including nanospheres, tree-like assembly morphology and belt-like superstructures. Optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and fluorescence spectrography were employed to characterize the self-assemblies.

Owing to the outstanding mechanical performance, diglycidyl ether of bisphenol A (DGEBA) becomes an important thermoset resin, but its brittleness and difficulties in degradation and recycling retard sustainable development. Herein, we have prepared several hyperbranched epoxy resins containing 1,3,5-hexahydro-s-triazine (HER-HTn, n = 3, 6, 12, 24) which showed versatility on modifying DGEBA, including simultaneous reinforcing and toughening function, rapid degradation and recycling, and good compatibility. The detailed results showed that the HER-HT12 could increase the flexural, impact and tensile strengths of cured DGEBA by 132.7%, 190.4%, and 57.7%, respectively, and also increase degradation degree from 37.2 wt% to 99.9 wt%. The mechanical performance of the cured HER-HTn/DGEBA reinforced in the beginning and then decreased with an increase in the content and the molecular weight of HER-HTn, however, their degradation degrees increased distinctly. The reinforcing and toughening mechanism and degradation mechanism of the composites were investigated by SEM micrographs and GC-MS spectra.

Hyperbranched epoxy resins (HERs) have attracted much interest due to improving homogeneously the ductility and strength of popular diglycidyl ether of bisphenol-A (DGEBA), but the preparation of HERs/DGEBA composites with low-temperature resistance and rapid degradation is still a challenge in the sustainable development of thermoset field. Here we represent self-curable hyperbranched epoxy resins (DSEHP-n, n = 3, 5, 7, 11) to modify DGEBA. DSEHP-n not only increases simultaneously the tensile strength, flexural strength, impact strength, modulus, and elongation by 64.8%, 38.1%, 93.7%, 70.4%, and 50%, respectively, and but also improve remarkably the low-temperature resistance and degradation degree. The improvement of mechanical properties is caused by the combined effect of crosslinking density, free volume, intermolecular cavity, hyperbranched topological structure, and good compatibility, the account of an in-situ reinforcing and toughening mechanism which substantiated by dynamic light scattering (DLS), SEM, DMA, and free volume analysis. The detailed analysis of degradation products from GC-MS spectra showed that the degradation of the composites was attributed to the cleavage of the C–N and ester bonds. This paper will bring a novel method to prepare highly-efficient degradable thermosets and composites.

Covalent organic frameworks (COFs) have emerged as promising electrode materials in flexible and wearable supercapacitors. However, achieving high electrical conductivity and high mechanical strength of flexible COF composite membranes is still a major challenge. Herein, we first prepared the COF complex by using hydroxyl-ended hyperbranched polymer (OHP) as a template via a simple solid-state mechanical mixing method, and the COF@OHP complex was then impregnated on a microporous carbon nanotube film (CNTF) to construct a composite membrane (CHCM) that can be prepared as CHCM electrodes for extensible and flexible supercapacitors. A large number of cavities, reactive end-groups and flexible polymer chains of the hyperbranched polymer are utilized to stabilize and disperse COFs and to enhance the COF-polymer’s interfacial interaction. CNTF is an attractive material for energy storage due to its excellent conductivity, slippability, flexibility, and high specific surface area. The CHCM electrode showed not only excellent electrochemical performance (high gravimetric capacitance of 249 F g−1 and charging-discharging stability of 80% after 10,000 cycles) in the relatively environmentally-friendly phosphoric acid (H3PO4) electrolyte, but also a high tensile strength of 180 MPa and an elongation of 10%. The gravimetric capacitance of the CHCM electrode reached 425 F g−1 in 2 M aq. H2SO4 electrolyte. This work will demonstrate a promising strategy for preparing wearable and flexible supercapacitors with high mechanical strength with potentially wide applications.

In this work, an efficient renewable approach to the toughening and strengthening of epoxy resins is presented by using agricultural byproducts. The resulting epoxy exhibits low viscosity and good mechanical performance and thermal properties, without sacrificing stiffness. First, we synthesized epoxidized konjac fly powder (EKFP) from konjac fly powder, an agricultural byproduct. Subsequently, the resulting EKFP was successfully used as a green reactive diluent to simultaneously improve the toughness and strength of petroleum-based epoxy diglycidyl ether of bisphenol-A (DGEBA). The experimental results indicated that the free volume of the epoxy resins was increased with the incorporation of the EKFP. The fracture morphology of the resulting epoxy thermosets displayed shallow cleavages and roughness that contribute to the increased toughness. The addition of the EKFP to the DGEBA significantly improved the tensile strength, flexural strength, and impact strength of the resulting epoxy thermosets. The tensile strength, tensile modulus, flexural strength, impact strength, fracture toughness and fracture energy of epoxy thermosets with 20 wt% EFKP are increased by 61.2 %, 29.7 %, 24.5 %, 119.3 %, 83.3 % and 159.1 %, respectively. The enhancement of the toughness and strength was associated with the increased free volume and reduction in internal stress of the epoxy. The simultaneous reinforcement and enhancement of the resin’s toughness demonstrated the possibility to use the byproducts of konjac glucomannan production for the creation of high-performance bio-based epoxy thermosets, which have the potential to be employed in coatings, the aerospace industry, and various electronic applications.

Rapid and highly efficient degradation of cured thermoset epoxy resins is a major challenge to scientists. Here, degradable self-cured hyperbranched epoxy resins (DSHE-n, n = 1, 2, and 3) were synthesized by a reaction between 3-isocyanato-4-methyl-epoxy-methylphenylcarbamate and degradable epoxy-ended hyperbranched polyester (DEHP-n) prepared from maleicanhydride, citric acid, and epichlorohydrin. The chemical structure of DSHE-n was characterized by Fourier transform infrared and 1H NMR spectra. With an increase in DSHE-n molecular weight, the adhesion strength of self-cured DSHE-n films increases distinctly from class 1 to 4, and their pencil hardness remains about class B–2B. The study on the self-cured behavior and mechanism of DSHE-n shows that the carbamate group of the DSHE-n is decomposed into diamine group to react with epoxy group and form a cross-linked structure. The self-cured DSHE-n films were degraded completely in 2 h at 90 °C in the mixed solution of hydrogen peroxide (H2O2) and N,N-dimethylformamide under atmospheric pressure and produced the raw material citric acid, indicating good degradation performance and recyclable property of DSHE-n.

A GSH sensitive nanocarrier (G4-DOX-Angiopep-PEG), with Angiopep-2 as a dual-targeting group and doxorubicin (DOX) as the therapy drug, was constructed by covalently conjugating them on the periphery of fourth generation PAMAM dendrimers (G4 PAMAM), aiming for an enhancement of BBB transportation and drug accumulation in glioma cells. It was found that the DOX release reached 44% with the concentration of GSH at 10 mM in the system, while only 3% DOX was released at pH 7.4 without GSH. The in vitro assay of transport across the BBB model showed that G4-DOX-Angiopep-PEG delivered 11% of DOX in a period of 12 h. The carrier could internalize into C6 glioma cells through low-density lipoprotein receptor-related protein (LRP)-mediated transcytosis. The accumulation of DOX in the tumor site was increased due to the targeting effects of Angiopep-2 via LRP-mediated endocytosis, which resulted in the volume of the avascular C6 glioma spheroids being effectively reduced in vitro.

The single crystal of M-4-B was obtained by attaching the boron of BH3 to the amine linker between a tetraphenylethylene (TPE) unit and rhodamine B. M-4-B showed a novel sequential tricolor switching from dark blue to bluish-green and to a reddish color upon grinding. The boron atom played a key role in developing the single crystal.

A novel hyperbranched flame-retardant polymer (referred to as ITA-HBP) was synthesized from itaconic anhydride as a renewable starting material. Upon the incorporation of ITA-HBP, both the toughness and flame-retarding ability of epoxy resins with low phosphorus contents increased simultaneously increased the toughness and flame retardant properties of epoxy resin with low phosphorus contents. The impact strength, fracture toughness and fracture energy of the epoxy resins are significantly enhanced by 133.2%, 78.7% and 124.7% respectively due to the in situ reinforcing and toughening effects induced by ITA-HBP. At the same time, the incorporated ITA-HBP exhibited a remarkable flame-retarding activity in the gas phase due to the production of phosphorus radicals and in the condensed phase due to the formation of a phosphorus-rich char layer of the epoxy resin. The addition of ITA-HBP considerably reduced the peak heat release rate, total heat release and smoke release of the epoxy resin. At a phosphorus content of 0.26 wt%, the ITA-HBP/epoxy thermosets scored V-0 rating in the UL-94 test and showed a limiting oxygen index of 36.3%.

The accelerating and thorough treatment of chronic wounds still represents a major unmet medical need owing to the complex symptoms resulting from metabolic disorder of the wound microenvironment. Although numerous strategies and bioactive hydrogels are developed, an effective and widely used method of chronic wound treatment remains a bottleneck. With the aim to accelerate chronic wound healing, many hydrogel dressings with antioxidant functions have emerged and are proven to accelerate wound healing, especially for chronic wound repair. The new strategy in chronic wound treatment brought by antioxidant hydrogels is of great significance to human health. Here, the application of antioxidant hydrogels in the repair of chronic wounds is discussed systematically, aiming to provide an important theoretical reference for the further breakthrough of chronic wound healing.

We herein report the self-assemblies of H4tcbpe-MA by using 1,1,2,2-tetrakis (4-(4-carboxy-phenyl) phenyl) ethane (H4tcbpe) and melamine (MA) as building blocks. It was found that H4tcbpe-MA only gave weak emission in dimethyl formamide (DMF) solution, while strong fluorescence was observed upon addition of water in the solution (fw > 60%), implying their notable aggregation induced emission (AIE) property. Interestingly, the self-assemblies of H4tcbpe-MA showed various morphologies by changing the ratio of MA, evidenced by optical microscope (OM) and scanning electron microscopy (SEM) measurements. Nanofibers, tree-like, cuboidal microstructures and microbelts were generated with the ratio of H4tcbpe-MA at 1:0, 1:1.5, 1:3.0 and 1:6.0, respectively. The powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements indicated that the ionic interaction, hydrogen bonding (H-bonding) and π-π stacking were the main driving forces for the fabrication of H4tcbpe-MA assemblies. It is worth noting that the self-assemblies displayed different emission colors variation dependence on the MA concentration- and relative humidity (RH). The photo-oxidation behavior of H4tcbpe-MA in solution was also investigated under visible light and 254 nm UV light.

Benefiting from the high binding affinity of 1,3,6,8-tetrakis(p-benzoic acid) pyrene (H4TBAPy) with three different amines (urea, melamine (MA) and terminal amino hyperbranched polymer (HP)), H4TBAPy produced self-assemblies with various morphologies, such as small flower-like, long fibers, three-dimensional (3D) flower shape and banana-like etc. Fluorescence spectra, dynamic light scattering (DLS), optical micrographs (OM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD) patterns, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were employed to monitor the self-assembly process and characterize the resultant assemblies. It was found that the π-π stacking of the planar aromatic pyrene core of H4TBAPy, electrostatic interaction and hydrogen bonding (H-bonding) interactions between the carboxylic acid group (-COOH) of H4TBAPy and the amino group of urea, MA, HP were the main driving forces for the self-assembly processes. This work may provide a powerful method to construct well-defined nanostructures with different morphologies by non-covalent interactions of two components.

Hyperbranched polymeric ionic liquids (HBPILs) with varying alkyl chain length have been synthesized and used as efficient catalysts for benzoxazine/epoxy thermosets. The values of activation energies for the thermal polymerization of benzoxazine/epoxy thermosets increase with increasing the alkyl chain length of HBPILs. The HBPILs significantly enhance the toughness of benzoxazine/epoxy thermosets. The phase morphologies of the benzoxazine/epoxy thermosets change from a homogeneous structure to a sea-island structure upon increasing the alkyl chain length of HBPILs, while the concentration changes were altered the interface behaviors between HBPILs and benzoxazine/epoxy. As the benzoxazine/epoxy thermosets formed phase separation structure, the toughness is significant improved compared to that of the continuous phase morphology. Moreover, the addition of HBPILs simultaneously improves the glass transition temperature (T g ) and thermal stability of benzoxazine/epoxy thermosets.

Prevention of Ru dissolution is essential for steady CO tolerance of anodic electrocatalysts in direct methanol fuel cells. Here, we demonstrate a facile way to stabilize Ru atoms by decorating commercial CB/PtRu with SiO2, which shows a six-fold higher stability and similar activity toward a methanol oxidation reaction leading to no discernible degradation in fuel cell performance compared to commercial CB/PtRu electrocatalysts. The higher stability and stable CO tolerance of SiO2-decorated electrocatalysts originate from the SiO2 coating, since Ru atoms are partially ionized during SiO2 decorating, resulting in difficulties in dissolution; while, in the case of commercial CB/PtRu, the dissolved Ru offers active sites for Pt coalescences and CO species resulting in the rapid decay of the electrochemical surface area and fuel cell performance. To the best of our knowledge, this is the first study about the stabilization of Ru atoms by SiO2. The highest stability is obtained for a PtRu electrocatalyst with negligible effect on the electrochemical properties.