Layered Double Hydroxide as Cordycepin Delivery Nanocarrier

Layered double hydroxides (LDHs), also called “anionic clays”, have received considerable attention due to their technological importance in catalysis, adsorption, optics, nanocomposite engineering materials and medical science1-5. LDHs are layered mate…     

Optical, structural and adsorption properties of zinc peroxide/hydrogel nanohybrid films

Hybrid nanofilms from zinc-peroxide/poly(acrylamide) (ZnO₂/PAAm) and zinc-peroxide/poly(N-isopropyl-acrylamide) (ZnO₂/PNIPAAm) were prepared using the photopolymerization procedure. The thin layers were prepared by the combination of the Layer-by-Layer (LbL) self-assembly method and photopolymerization using UV light in every step of the procedure. The hybrid multilayer films consisting of layers of zinc peroxide nanoparticles and hydrogel alternating in a sandwich-like fashion with thicknesses of 65-246 nm. The chemical structures of the hybrid films were investigated by FTIR spectroscopy, their morphology was studied by atomic force microscopy (AFM). The build up of the films was studied by measuring the optical reflection spectrum, and we have calculated the refractive index and layer thickness of the hybrid layers using simulating software. The adsorption properties of the ZnO₂/hydrogel nanohybrid composite networks were investigated by measuring water and ethanol vapour adsorption by a quartz crystal microbalance (QCM). It was established that on partially hydrophobic ZnO₂/PNIPAAm hybrids the adsorbed amounts were lower, against the hydrophilic ZnO₂/PAAm film the vapour amount was higher. These results correspond to those of the bulk gel swelling results.     

Effect of nanocomposite of attapulgite/EVA on flow behavior and wax crystallization of model oil

Nanocomposites of attapulgite (ATT)/ethylene vinyl acetate copolymer (EVA) were prepared with organically modified ATT covering in EVA. Organically modified ATT was prepared using KH550 and organic acid. The effect of nano-hybrid on the flow behavior of model oil containing 15?wt% wax was evaluated. The wax crystallization and crystal morphology of the model oil at low temperature were observed by polarizing optical microscopy (POM). The results indicated that the nano-hybrid with long-chain organic acid-modified ATT exhibited a better effect compared with the nano-hybrid with short-chain organic acid-modified ATT, pure EVA. In addition, it is interesting to note that EVA (VA?=?32%)/stearic acid-modified ATT composite polymeric pour-point depressant (PPD) S-AtPPD(32) provided better cold-flow improvement for the model oil than EVA (VA?=?32%)-modified nano-SiO₂ composite PPD N-SiPPD (32) with a low dose, which resulted in a regular, bar-shaped, and uniform arrangement of wax morphologies. The pour point of the model oil was reduced from 30°C to ?1°C when doped at 200?ppm S-AtPPD(32).     

The influence of mesoporous SiO2‐graphene hybrid improved the flame retardancy of epoxy resins

A novel mesoporous SiO₂‐graphene nanohybrid was successfully synthesized by a 1‐pot hydrothermal synthesis method using tetraethylortho silicate and graphene oxide as initial materials to improve the dispersion of graphene in epoxy matrix. Subsequently, the SiO₂‐graphene nanohybrids were added into epoxy resin to investigate their fire behaviors. It was found that the incorporation of the as‐prepared SiO₂‐graphene nanohybrids into epoxy resin obviously increased the flame retardancy, compared with those of neat epoxy. This attractive feature of SiO₂‐graphene epoxy nanocomposites was attributed to the barrier effect as well as the labyrinth effect contributed by SiO₂‐graphene in EP resin.     

Yolk–shell microspheres assembled from Preyssler‐type NaP5W30O11014− polyoxometalate and MIL‐101(Cr) metal–organic framework: A new inorganic–organic nanohybrid for fast and selective removal of cationic organic dyes from aqueous media

Novel inorganic–organic yolk–shell microspheres based on Preyssler‐type NaP₅W₃₀O₁₁₀^14? polyoxometalate and MIL‐101(Cr) metal–organic framework (P₅W₃₀/MIL‐101(Cr)) were synthesized by reaction of K_12.5Na_1.5[NaP₅W₃₀O₁₁₀], Cr(NO₃)₃·9H₂O and terephthalic acid under hydrothermal conditions at 200°C for 24 h. The as‐prepared yolk–shell microspheres were fully characterized using various techniques. All analyses confirmed the incorporation of the Preyssler‐type NaP₅W₃₀O₁₁₀^14? polyoxometalate into the three‐dimensional porous MIL‐101(Cr) metal–organic framework. The results revealed that P₅W₃₀/MIL‐101(Cr) demonstrated rapid adsorption of cationic methylene blue (MB) and rhodamine B (RhB) with ultrahigh efficiency and capacity, as well as achieving rapid and highly selective adsorption of MB from MB/MO (MO = methyl orange), MB/RhB and MB/RhB/MO mixtures. The P₅W₃₀/MIL‐101(Cr) adsorbent not only exhibited a high adsorption capacity of 212 mg g^?1, but also could quickly remove 100% of MB from a dye solution of 50 mg l^?1 within 8 min. The effects of some key parameters such as adsorbent dosage, initial dye concentration and initial pH on dye adsorption were investigated in detail. The equilibrium adsorption data were better fitted by the Langmuir isotherm. The adsorption kinetics was well modelled using a pseudo‐second‐order model. Also, the inorganic–organic hybrid yolk–shell microspheres could be easily separated from the reaction system and reused up to four times without any change in structure or adsorption ability. The stability and robustness of the adsorbent were confirmed using various techniques.     

Photocatalytic degradation of methyl orange using hematoporphyrin/N‐doped TiO2 nanohybrids under visible light: Kinetics and energy consumption

Various nitrogen‐doped titania particles were prepared and, for visible light sensitizing, the biological pigment hematoporphyrin was grafted onto their surfaces. The nanohybrid products were characterized using X‐ray diffraction, Fourier transform infrared and ultraviolet–visible spectroscopies and Brunauer–Emmett–Teller surface area analysis. A high‐performance visible light helical flow photoreactor was designed and used for the photocatalytic degradation of methyl orange (MO) over these photocatalyst products. Accordingly, response surface methodology was employed for design of experiments and optimization. The influencing parameters were initial N/Ti molar ratio, dosage of nanohybrids and solution pH. These parameters were statistically significant and a quadratic correlation was developed for degradation efficiency (DE) variations. A maximum DE of 89.2% was attainable, after 60 min treatment, under the optimum conditions of initial N/Ti molar ratio of 4.93 (ca 5), nanohybrid dosage of 0.73 g l⁻¹ and pH of 4.8. The MO degradation kinetics over the catalyst surface followed the modified Langmuir–Hinshelwood model. The important role of hydroxyl radicals was confirmed using mannitol scavenger. Performing the photocatalytic reaction with the developed set‐up showed excellent efficiency and energy consumption in comparison with similar processes.     

The role of aromaticity on the building of nanohybrid materials functionalized with metalated (Au(III), Ag(III), Cu(III)) extended porphyrins and single‐walled carbon nanohorns: A theoretical study

An ab initio, systematic study on the aromaticity involving the group of metalated extended porphyrins, termed meso‐hexakis(pentafluorophenyl)‐substituted[26]hexaphyrin(1.1.1.1.1.1) (HP), was performed for the first time. The aromatic behavior of the system shifted to antiaromatic in the [28]HP analogue, due to the presence of hydrogen atoms that break the orbital symmetry. The absorption bands observed in the experiment were assigned to an intraligand charge transfer, where the intrametallic character is also important. The excited states reveal the absorption of visible light and the possibility of electronic transfer to different systems. We propose a system such as single‐walled carbon nanohorns (SWCNHs), due to their special electronic properties, and predict a novel nanohybrid material. The evidence of electronic communication between both species is presented in this work. The HP aromaticity and the spatial configuration of the interaction with SWCNHs are also related to the strength of electronic transfer among the systems, making the HP metalated antiaromatic species and their corresponding nanohybrids potential candidates to be used as building blocks in photovoltaic cell materials. © 2012 Wiley Periodicals, Inc.     

Synthesis and characterization of new organic–inorganic nanohybrid film (TBA)PWFe/PVA/CTS as an efficient and reusable amphiphilic catalyst for ODS of real fuel

In this work, we report a new catalytic oxidative desulfurization (CODS) system based on (TBA)PWFe/PVA/CTS nanohybrid film as a highly active catalyst. The nanohybrid material was successfully fabricated by the composition of tetra (n‐butyl) ammonium salt of Fe‐substituted phosphotungstate, ((n‐C₄H₉)₄N)₄[PW₁₁Fe(H₂O)O₃₉] abbreviated as (TBA)PWFe, polyvinyl alcohol (PVA), and chitosan (CTS). The composite was characterized using various analytical techniques including FT‐IR, UV–vis, XRD, and SEM. The results revealed the hydrogen‐bonding interaction between inorganic (TBA)PWFe clusters and organic polymers. The catalytic activity of (TBA)PWFe/PVA/CTS was evaluated in the CODS of real gas oil. Also, the solutions of heterocyclic thiophenic compounds (HTCs) in n‐heptane were tasted as simulated fuels. It was found that the removal efficiency of HTCs in the presence of (TBA)PWFe/PVA/CTS catalyst reached as high as 95% at 60 °C after 2 h. The significant catalytic performance of the nanohybrid film might be attributed to its amphiphilicity and multifunctional active sites, which enhances adsorption and oxidation of sulfur compounds. Moreover, the (TBA)PWFe/PVA/CTS composite can be easily recovered and reused by simple filtration, making it a suitable catalyst for cleaner processing.     

The Sensitized Solid‐Phase Electrochemiluminescence of Electrodeposited Poly‐Luminol/Aniline on AuAg/TiO2 Nanohybrid Functionalized Electrode for Flow Injection Analysis

In this study, a copolymer of luminol with aniline is electrochemically deposited onto the AuAg/TiO₂ nanohybrid functionalized indium tin oxide coated glass. It is used as a reagentless electrochemiluminescent (ECL) electrode for flow‐injection‐analysis (FIA). The properties of this solid phase ECL electrode are characterized by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy etc. It has stronger ECL emission, sensitive response for target analytes and excellent stability. The so‐prepared ECL electrode shows sensitive response to reactive oxygen species thereafter to be applied for determination of hydrogen peroxide with FIA mode. Under optimized conditions, a mass detection limit of 0.822 pg of hydrogen peroxide was obtained. Thus the hydrogen peroxide residues in samples were detected with satisfactory result.     

Influence of pH on the Formation of Tyr/LDH Nanohybrids

In this article, the intercalation of amphoteric amino acid tyrosine (Tyr) into LDH by the co‐precipitation method is systematically examined. The influence of pH values has been examined. Powder X‐ray diffraction, Fourier transform infrared spectroscopy, specific surface areas and pore size distributions, and thermal analysis have been employed for the characterization of the nanocomposites. The nanohybrids were found to have expanded layered structure, indicating that the biomolecules were intercalated into the gallery as anions. The intercalation of amino acids resulted in the increase of surface areas and pore volumes, and these values increased with increasing of biomolecules intercalated. TEM analysis revealed that with the decrease of pH values, the nanohybrids changed from hexagonal particles to spherical ones. Moreover, the configuration of Tyr anions varied under different pH values, the configuration changing from monolayer to bilayers with more biomolecules in the gallery.