Curing behavior of sodium carboxymethyl cellulose/epoxy/MWCNT nanocomposites.

The surfactant-assisted preparation of carbon nanotube (CNT)/polymer composites has attracted the attention of scientists around the world. Here, CNT/epoxy nanocomposites were prepared using sodium carboxymethyl cellulose (CMC). The effect of CMC on the curing behaviors of epoxy resin (E44) and CNTs/E44 was studied using differential scanning calorimetry (DSC). The curing kinetics of the CMC/CNTs/E44 systems were examined using methods where the activation energy (E) is a constant and where E is a variable, respectively. The change of E with the conversion (α) was calculated using the Starink isoconversional method. For the E44 system, a significant variation of E was observed when the conversion increased from 0.05 to 0.95. The E variable method was introduced to this system to describe this phenomenon. In contrast to the method where E is a constant, the E variable method has better agreement with the experimental data. With these two methods, the curing kinetics of the CMC/CNTs/epoxy system can be understood comprehensively and accurately. Ultimately, the dynamic mechanical properties of neat E44, CMC/E44 and CMC/CNTs/E44 were investigated and compared, which showed that CMC/E44 had a higher storage modulus (E m) than the neat E44 and CMC/CNTs/E44 systems, and the CMC/CNTs/E44 system had a higher glass transition temperature (T g) and damping factor (tan δ) than the neat E44 and CMC/E44 systems.

Comparison of the antioxidant activities of nonfumigated and sulphur-fumigated Chrysanthemum morifolium cv. Hang-ju induced by oxidative stress.

CONTEXT: The traditional drying method, sun drying, for Chrysanthemum morifolium Ramat. cv. Hang-ju (Compositae) (HJ) is widely replaced by sulphur fumigation (SF), which has an unknown effect on its efficacy. OBJECTIVE: To investigate protective effects of nonfumigated HJ (NHJ) and sulphur-fumigated HJ (SHJ) water extracts against oxidative stress and lipid peroxidation. MATERIALS AND METHODS: Sprague-Dawley rats were administered high-fat diet to induce hyperlipidaemia and randomly divided into eight groups (n = 6): control, fenofibrate, NHJ and SHJ extracts (1, 2 or 4 g crude drugs/kg/d; intragastric administration for 8 weeks). Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected. Human umbilical vein endothelial cells (HUVECs) were treated with NHJ and SHJ extracts (50, 100 or 200 µg/mL) for 24 h, followed by oxidized low-density lipoprotein (ox-LDL, 20 µg/mL) for 2 h in vitro. Cellular reactive oxygen species (ROS), SOD and MDA levels and apoptosis were evaluated. RESULTS: NHJ was more effective than SHJ in decreasing serum TG, TC, LDL-C, LDL/HDL and MDA while increasing serum HDL-C and SOD levels at high doses. SHJ (IC50=19.9 mg/mL) suppressed HUVEC growth stronger than NHJ (IC50=186.7 mg/mL). At 200 µg/mL, NHJ was more effective than SHJ in downregulating ROS and MDA levels, reducing HUVECs apoptosis rate and elevating SOD activity in ox-LDL-treated HUVECs. CONCLUSIONS: SF causes oxidative damage and attenuates antioxidative activity in ox-LDL-treated HUVECs, which promotes lipid peroxidation. SF is not recommended for processing HJ.

One-step, low-cost, mussel-inspired green method to prepare superhydrophobic nanostructured surfaces having durability, efficiency, and wide applicability.

Various oils discharged from daily life and industrial production, as well as frequent oil spillages, have led to severe water pollution and ecological problems. Mussel-inspired polydopamine has been widely applied for fabrication of superhydrophobic materials for oil/water separation. However, the need of additional nanoparticles via tedious steps to construct nanostructures, and the high cost of dopamine itself limit its practical applications. Moreover, the application modes of superhydrophobic materials for oil/water separation are monotonous, which will limit the applied range of the superhydrophobic materials. For example, superhydrophobic sponge was usually used for adsorbing oil droplets or oil spills from water, while superhydrophobic fabric or mesh was usually used for separating bulk layered oil/water mixture. Therefore, developing simple and low-cost mussel-inspired surface modification strategy toward superhydrophobic materials, as well as diverse application modes for oil/water separation, is still highly desired. In this study, superhydrophobic sponge and fabric with nanostructures, which exhibits excellent performance for diverse oil/water separation, have been fabricated through a novel one-step and cost-effective mussel-inspired approach. The resultant superhydrophobic sponge exhibits outstanding oil absorption capability (weight gains up to 8860%), while the superhydrophobic fabric can effectively separate oil/water mixture. Moreover, diverse modes for oil/water separation have been developed for the first time. For example, water-in-oil emulsion can be highly-efficient separated by a compressed superhydrophobic sponge (~1800L m-2h-1 bar-1 for water-in-oil emulsion, and above 99% rejection rate for water droplets), while crude oil spills can be efficiently collected by a superhydrophobic boat (above 98%).

Two novel aromatic hydrocarbons: facile synthesis, photophysical properties and applications in deep-blue electroluminescence.

Two efficient novel fluorescent naphthalene and fluorene-based aromatic hydrocarbon isomers (1 and 2) are prepared and investigated for organic electroluminescence. These compounds show bright violet to deep-blue emission, narrow full width at half maximum (52 nm), and high photoluminescence efficiency (e.g. 0.61 in CH2Cl2, 0.67 in film). Alternation of substituent position on the naphthalene moiety can give rise to remarkable emission variation. The relatively large torsion angle between naphthalene and fluorene suppresses the π-π interactions by weakening the intermolecular interactions in the solid state, which can result in highly efficient fluorescence. Moreover, the 1931 Commission Internationale de L'Eclairage coordinates and maximum emission peak for deep-blue electroluminescence based on 1 are (0.16, 0.08) and 410 nm, respectively.

"Water-in-salt" electrolyte enhanced high voltage aqueous supercapacitor with carbon electrodes derived from biomass waste-ground grain hulls.

To design high specific surface area and optimize the pore size distribution of materials, we employ a combination of carbonization and KOH activation to prepare activated carbon derived from ground grain hulls. The resulting carbon material at lower temperature (800, BSAC-A-800) exhibits a porous structure with a high specific surface area of 1037.6 m2 g-1 and a pore volume of 0.57 m3 g-1. Due to the synergistic structural characteristics, BSAC-A-800 reveals preferable capacitive performance, showing a specific capacitance as high as 313.3 F g-1 at 0.5 A g-1, good rate performance (above 73%), and particularly stable cycling performance (99.1% capacitance retention after 10 000 cycles at a current density of 10 A g-1). More importantly, the assembled symmetric supercapacitor using a water-in-salt electrolyte (17 m NaClO4) with high discharge specific capacitance (59 F g-1 at 0.5 A g-1), high energy density (47.2 W h kg-1) and high voltage (2.4 V) represents significant progress towards performance comparable to that of commercial salt-in-water electrolyte supercapacitors (with discharge specific capacitance of 50 F g-1, energy densities of ∼28.1 W h kg-1 and voltages of 2.0 V).

The application of a non-doped composite hole transport layer of [MoO3/CBP] n with multi-periodic structure for high power efficiency organic light-emitting diodes.

A non-doped multi-periodic structure of composite hole transport layer of [MoO3/CBP] n was applied to organic light-emitting diodes. All devices with such hole transport layers showed low turn-on voltage of about 3 V, ultra-high luminance of >110 000 cd m-2, high current efficiency of >50 cd A-1, and high EQE of more than 15%. The optimized device exhibited power efficiency increase of 66% and 18% relative to the single periodic and doped structure OLEDs. The achievement of the reduced driving voltage and improved power efficiency can be attributed to the significantly enhanced hole injection and transport induced by the multi-periodic structure of composite hole transport layer, which was demonstrated via a series of hole-only devices. For improved hole injection and transport mechanism, we also provided a detailed discussion in combination with atomic force microscopy measurements.

Rational design of quinoxaline-based bipolar host materials for highly efficient red phosphorescent organic light-emitting diodes.

Two novel bipolar carbazole/diphenylquinoxaline-based host materials 3-(2,3-diphenylquinoxalin-6-yl)-9-phenyl-9H-carbazole (M1) and 3-(4-(2,3-diphenylquinoxalin-6-yl)phenyl)-9-phenyl-9H-carbazole (M2) have been rationally designed and synthesized. The phenyl spacer between the functionalized quinoxaline moiety and the carbazole moiety is also introduced to investigate its influence on their photophysical properties. The chemical structures, and thermal, photophysical and electrochemical properties of the two host materials were characterized and explored in detail. Red phosphorescent light-emitting diodes with M1 and M2 as hosts were prepared to explore their electroluminescent properties. Both M1 and M2 host-based red devices exhibit outstanding electroluminescent performance. For example, two red devices all realize good red emission with the maximum at 594 nm, the maximum external quantum efficiency and luminance can reach 14.66% and 28 619 cd m-2 for M1-based devices and 15.07% and 28 818 cd m-2 for M2-based devices, indicating compounds M1 and M2 designed in this work have potential applications in the development of high-performance monochrome and white OLEDs.

In vivo and in vitro anti-inflammatory effects of Sophora flavescens residues.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried roots of Sophora flavescens Ait. (Leguminosae) is traditionally used as antipyretic medicine to reduce inflammation. It is well known that alkaloids and flavonoids are the main constituents of S. flavescens. However, the clinical researches and applications of S. flavescens is mainly based on its water-extracted alkaloids, its flavonoids may still remain in residues and have been underused. With development and manufacturing of S. flavescens in recent years, more herb residues are being produced. Since they are typically treated as waste and dumped openly in landfill sites, which can cause pollution, there is a great need to explore these wastes as recyclable resources and increase their added value. To date, whether other bioactive components would be found in the residues of S. flavescens is still unknown. If the extraction method of these active ingredients was established, the residues of S. flavescens could be turned from the harm to a benefit and make great sense of the comprehensive utilization of S. flavescens resources. This study aimed to establish an extraction method of the residues of S. flavescens and investigate the anti-inflammatory effect of it both in vivo and in vitro. MATERIALS AND METHODS: Dried S. flavescens were decocted with distilled water firstly, then the residues were powdered and extracted with ethyl acetate by using ultrasonic wave. HPLC was utilized to analyze the chemical constituents of the water extracts of S. flavescens (WSF) and the ethyl acetate extracts of residues of S. flavescens (RSF). In vivo, the anti-inflammatory effect of WSF and RSF were evaluated using the xylene-induced auricle edema, acetic acid-induced peritoneal permeability and carrageenan-induced hind paw edema methods. In vitro, the inhibitory activities of WSF and RSF on NO, TNF-α, IL-6 and MCP-1 production of LPS-treated RAW264.7 cells were measured. RESULTS: The major ingredients of RSF were flavonoids, while WSF almost had no flavonoids. In vivo, WSF and RSF (200 mg/kg) could significantly inhibit the edema in the xylene-induced mice auricle edema and carrageenan-induced hind paw edema as well as the peritoneal permeability increased by acetic acid. They can also lower production levels of PGE2 in inflamed paw tissues. In vitro experimental results showed that RSF (25-100 µg/mL) could significantly inhibit the release of pro-inflammatory cytokines NO, TNF-α, IL-6 and MCP-1 on LPS-induced RAW264.7 cells. The in vitro suppress effect of WSF had no dose-response relationship. CONCLUSIONS: The residues of S. flavescens had obvious flavonoids with anti-inflammatory activity. This study provided evidence for the reuse of residues from S. flavescens in the food additive, medicine and cosmetic industries.

Metallopolymer precursors to L10-CoPt nanoparticles: synthesis, characterization, nanopatterning and potential application.

Ferromagnetic (L10 phase) CoPt alloy nanoparticles (NPs) with extremely high magnetocrystalline anisotropy are promising candidates for the next generation of ultrahigh-density data storage systems. It is a challenge to generate L10 CoPt NPs with high coercivity, controllable size, and a narrow size distribution. We report here the fabrication of L10 CoPt NPs by employing a heterobimetallic CoPt-containing polymer as a single-source precursor. The average size of the resulting L10 CoPt NPs is 3.4 nm with a reasonably narrow size standard deviation of 0.58 nm. The coercivity of L10 CoPt NPs is 0.54 T which is suitable for practical application. We also fabricated the L10 CoPt NP-based nanoline and nanodot arrays through nanoimprinting the polymer blend of CoPt-containing metallopolymer and polystyrene followed by pyrolysis. The successful transfer of the pre-defined patterns of the stamps onto the surface of the polymer blend implies that this material holds great application potential as a data storage medium.

Adsorption and aggregation behavior of tetrasiloxane-tailed surfactants containing oligo(ethylene oxide) methyl ether and a sugar moiety.

Three novel amphiphilic dicephalic (double-headed) surfactants containing oligo(ethylene-oxide)methyl-ether and a sugar moiety TGA-m (m = 1, 2, and 3) that incorporate a tetrasiloxane at the terminus of a hydrocarbon chain were designed and synthesized. Their surface activity and aggregation behavior in aqueous solution were systematically investigated by surface tension, dynamic light scattering (DLS), and transmission electron microscopy (TEM) techniques at 298 K. The surface tension measurements provided the critical aggregation concentration (CAC) and the surface tension at the CAC (γ(cac)). In addition, with application of the Gibbs adsorption isotherm, the maximum surface excess concentration (Γ(max)) and the minimum surface area/molecule (A(min)) at the air-water interface were estimated. The effect of EO chain length on the surface activity and aggregation behavior was also investigated. It was found that both the γ(cac) and the CAC were lower than those for reported traditional hydrocarbon surfactants. Aggregates of three surfactants, TGA-m (m = 1, 2, and 3), formed in aqueous solutions could be assigned as spherical vesicles as suggested by analysis using DLS and TEM. Moreover the formation of vesicles can be confirmed by the encapsulation of bromophenol blue. These results indicate that these three surfactants have excellent efficiencies of vesicle formation and surface tension reduction in the aqueous phase.