Nanocomposites

Distribution by Scientific Domains
Distribution within Polymers and Materials Science

Kinds of Nanocomposites

  • binary nanocomposite
  • blend nanocomposite
  • carbon nanotube nanocomposite
  • cellulose nanocomposite
  • clay nanocomposite
  • epoxy nanocomposite
  • hybrid nanocomposite
  • montmorillonite nanocomposite
  • nanotube nanocomposite
  • novel nanocomposite
  • nylon clay nanocomposite
  • organic nanocomposite
  • organoclay nanocomposite
  • polyethylene nanocomposite
  • polyimide nanocomposite
  • polymer nanocomposite
  • polymer-clay nanocomposite
  • polymeric nanocomposite
  • polypropylene nanocomposite
  • polypropylene-clay nanocomposite
  • polystyrene nanocomposite
  • polyurethane nanocomposite
  • pp nanocomposite
  • prepared nanocomposite
  • resultant nanocomposite
  • silica nanocomposite
  • silicate nanocomposite
  • superabsorbent nanocomposite
  • ternary nanocomposite

  • Terms modified by Nanocomposites

  • nanocomposite coating
  • nanocomposite containing
  • nanocomposite fiber
  • nanocomposite film
  • nanocomposite foam
  • nanocomposite formation
  • nanocomposite hydrogel
  • nanocomposite material
  • nanocomposite particle
  • nanocomposite sample
  • nanocomposite structure
  • nanocomposite system
  • nanocomposite thin film

  • Selected Abstracts


    Direct Electrochemistry of Hemoglobin Immobilized on Colloidal Gold-Hydroxyapatite Nanocomposite for Electrocatalytic Detection of Hydrogen Peroxide

    ELECTROANALYSIS, Issue 2 2009
    Juan You
    Abstract A novel nanocomposite of colloidal gold (GNPs) and hydroxyapatite nanotubes (Hap) was prepared for immobilization of a redox protein, hemoglobin (Hb), on glassy carbon electrode. The immobilized Hb showed fast direct electron transfer and excellent electrocatalytic behavior toward reduction of hydrogen peroxide. A synergic effect between GNPs and Hap for accelerating the surface electron transfer of Hb was observed, which led to a pair of redox peaks with a formal potential of (,340±2) mV at pH,7.0, and a new biosensor for hydrogen peroxide with a linear range from 0.5 to 25,,M and a limit of detection of 0.2,,M at 3,. Owing to the good biocompatibility of the nanocomposite, the biosensor exhibited good stability and acceptable reproducibility. The as-prepared nanocomposite film provided a good matrix for protein immobilization and biosensor preparation. [source]


    Synthesis and Characterization of MWNTs/Au NPs/HS(CH2)6Fc Nanocomposite: Application to Electrochemical Determination of Ascorbic Acid

    ELECTROANALYSIS, Issue 16 2008
    Jian-Ding Qiu
    Abstract In this article, a detailed electrochemical study of a novel 6-ferrocenylhexanethiol (HS(CH2)6Fc) self-assembled multiwalled carbon nanotubes-Au nanoparticles (MWNTs/Au NPs) composite film was demonstrated. MWNTs/Au NPs were prepared by one-step in situ synthesis using linear polyethyleneimine (PEI) as bifunctionalizing agent. HS(CH2)6Fc, which acted as the redox mediator, was self-assembled to MWNTs/Au NPs via Au-S bond. Transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier transformed infrared absorption spectroscopy (FT-IR), UV-visible absorption spectroscopy, and cyclic voltammetry were used to characterize the properties of the MWNTs/Au NPs/HS(CH2)6Fc nanocomposite. The preparation of the nanocomposite was very simple and effectively prevented the leakage of the HS(CH2)6Fc mediator during measurements. The electrooxidation of AA could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique performance of MWNTs/Au NPs. The nanocomposite modified electrode exhibited excellent catalytic efficiency, high sensitivity, good stability, fast response (within 3,s) and low detection limit toward the oxidation of AA at a lower potential. [source]


    Fabrication and Application of a Novel Modified Electrode Based on Multiwalled Nanotubes/Cerium(III) 12-Tungstophosphoric Acid Nanocomposite

    ELECTROANALYSIS, Issue 11 2008
    Bin Fang
    Abstract A novel multiwalled nanotubes (MWNTs)/Cerium(III) 12 - tungstophosphoric acid (CePW) nanocomposite film glassy carbon electrode was prepared in this paper. Electrochemical behaviors of the CePW/MWNTs modified electrode were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This modified electrode brought new capabilities for electrochemical devices by combining the advantages of carbon nanotubes, rare-earth, and heteropoly-acids. The results demonstrated that the CePW/MWNTs modified electrode exhibited enhanced electrocatalytic behavior and good stability for the detection of guanine and adenine in 0.1,M PBS (pH,7.0). The experimental parameters were optimized and a direct electrochemical method for the simultaneous determination of guanine and adenine was proposed. The detection limit (S/N=3) for guanine and adenine was 2.0×10,8,M and 3.0×10,8,M, respectively. Further, the acid-denatured calf thymus DNA was also detected and the result was satisfied. [source]


    Magnetically Controllable Silver Nanocomposite with Multifunctional Phosphotriazine Matrix and High Antimicrobial Activity

    ADVANCED FUNCTIONAL MATERIALS, Issue 14 2010
    Panagiotis Dallas
    Abstract A recently developed multi-functional phosphotriazine-based polymer is used as a matrix for embedding ,-Fe2O3 nanoparticles as well as a suitable chemical template for surface modification with silver nanoparticles. For the primary magnetic modification, maghemite nanoparticles are surface modified with oleic acid in order to render them organophilic and to prevent the aggregation of the nanoparticles. This aggregation could occur as the polymer synthesis, based on reaction of phosphonitrilic chlorine and 1,4-phenylenediamine, takes place in toluene. The surface active amine units of the polymer structure enable the reduction of silver cations to silver nanoparticles, which are well attached and finely dispersed on its surface. The developed nanocomposite represents one of the few magnetically controllable antibacterial agents based on silver nanoparticles. Magnetic measurements reveal the completely suppressed interactions among maghemite nanoparticles because of their perfect surface coating with an organic surfactant and fine dispersion inside the polymer matrix. This magnetic nanocomposite exhibits a high antibacterial and antifungal activity as proven by tests with nine bacterial strains and four candida (yeast genus) species. For the majority of the tested species, the minimum-inhibition concentrations are below 100,mg,L,1, which is comparable to their equivalent minimum-inhibition concentrations in colloidal silver systems. [source]


    Signal-On Electrochemiluminescence Biosensors Based on CdS,Carbon Nanotube Nanocomposite for the Sensitive Detection of Choline and Acetylcholine

    ADVANCED FUNCTIONAL MATERIALS, Issue 9 2009
    Xiao-Fei Wang
    Abstract This work describes for the first time signal-on electrochemiluminescence (ECL) enzyme biosensors based on cadmium sulfide nanocrystals (CdS NCs) formed in situ on the surface of multi-walled carbon nanotubes (MWCNTs). The MWCNT,CdS can react with H2O2 to generate strong and stable ECL emission in neutral solution. Compared with pure CdS NCs, the MWCNT,CdS can enhance the ECL intensity by 5.3-fold and move the onset ECL potential more positively for about 400,mV, which reduces H2O2 decomposition at the electrode surface and increases detection sensitivity of H2O2. Furthermore, the ECL intensity is less influenced by the presence of oxygen in solution. Benefiting from these properties, signal-on enzyme-based biosensors are fabricated by cross-linking choline oxidase and/or acetylcholine esterase with glutaraldehyde on MWCNT,CdS modified electrodes for detection of choline and acetylcholine. The resulting ECL biosensors show wide linear ranges from 1.7 to 332,µM and 3.3 to 216,µM with lower detection limit of 0.8 and 1.7,µM for choline and acetylcholine, respectively. The common interferents such as ascorbic acid and uric acid in electrochemical enzyme-based biosensors do not interfere with the ECL detection of choline and acetylcholine. Furthermore, both ECL biosensors possess satisfying reproducibility and acceptable stability. [source]


    Stable Blue Emission from a Polyfluorene/Layered-Compound Guest/Host Nanocomposite,

    ADVANCED FUNCTIONAL MATERIALS, Issue 7 2006
    E. Aharon
    Abstract In this study a blue-light-emitting conjugated polymer, poly(9,9-dioctylfluorene), is confined to the interlayer space of inorganic, layered metal dichalcogenide materials, metallic MoS2, and semiconducting SnS2. The nanocomposites are prepared through Li intercalation into the inorganic compound, exfoliation, and restacking in the presence of the polymer. X-ray diffraction and optical absorption measurements indicate that a single conjugated polymer monolayer, with an overall extended planar morphology conformation, is isolated between the inorganic sheets, so that polymer aggregation or ,,, interchain interactions are significantly reduced. Photoluminescence (PL) measurements show that the appearance of the undesirable green emission observed in pristine polymer films is suppressed by incorporating the polymer into the inorganic matrix. The blue emission of the intercalated polymer is stable for extended periods of time, over two years, under ambient conditions. Furthermore, the green emission is absent in the PL spectra of nanocomposite films heated at 100,°C for 7,h in air with direct excitation of the keto defect. Finally, no green emission was observed in the electroluminescence spectrum of light-emitting devices fabricated with a polymer-intercalated SnS2 nanocomposite film. These results support the proposed hypothesis that fluorenone defects alone are insufficient to generate the green emission and that interchain interactions are also required. [source]


    Efficient Photosensitization and High Optical Gain in a Novel Quantum-Dot-Sensitized Hybrid Photorefractive Nanocomposite at a Telecommunications Wavelength,

    ADVANCED FUNCTIONAL MATERIALS, Issue 5 2005
    Choudhury, K. Roy
    Abstract A high-performance hybrid polymeric photorefractive nanocomposite operating at the telecommunications wavelength of 1.34,,m is presented. The photorefractive nanocomposite is sensitized with PbS nanocrystals synthesized via a hot colloidal route. Photoconductivity experiments confirm and quantify the photocharge-generation quantum efficiency of the nanocrystals. A pronounced two-beam coupling effect at the operation wavelength is observed, leading to very high optical gains. Temporal evolution of the photorefractive growth process is also studied. [source]


    Interfacial Stress Transfer in a Graphene Monolayer Nanocomposite

    ADVANCED MATERIALS, Issue 24 2010
    Lei Gong
    It is demonstrated from stress-induced Raman bands shiftsthat stress can be transferred from a polymer matrix to a graphene monolayer (see image) in a model nanocomposite. It is shown further that the behavior can be modeled using continuum mechanics and that the interface between the graphene and the polymer breaks down at a shear stress of the order of 2,MPa. [source]


    Graphite-Grafted Silicon Nanocomposite as a Negative Electrode for Lithium-Ion Batteries

    ADVANCED MATERIALS, Issue 46 2009
    Cédric Martin
    p -Phenylenediamine is used to successively generate two aryl radicals that are required to link silicon nanoparticles to graphite flakes by a phenyl bridge and form new silicon/graphite nanocomposites (see image). Such a covalent grafting technique enhances the cycling ability and the gravimetric capacity of the nano composite-based electrode in a lithium-ion battery. [source]


    Space Charge Measurement in MgO/LDPE Nanocomposite up to Breakdown under DC Ramp Voltage

    IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 4 2010
    Yoshinobu Murakami Member
    Abstract To understand the basic electric properties of nanosized magnesium oxide (MgO)/low-density polyethylene (LDPE) nanocomposites under an applied DC voltage, the DC breakdown strength and space charge up to the breakdown under a DC ramp voltage were investigated. Compared to that of the LDPE sample, the sample containing a MgO nanofiller (hereafter, called a nanocomposite) had a higher DC breakdown strength. In the case of the LDPE sample, the homo charges, which contained a large negative charge and a small positive charge, were only observed near the electrodes just prior to breakdown. However, in the case of the nanocomposite sample, the positive charge increased as the average field increased until the average field reached a certain value. After that, the positive charge decreased as the average field increased until breakdown occurred. The field enhancement rate (=maximum field/average field) of the nanocomposite sample increased with the average field, until it became saturated. After peaking, the field enhancement rate of the nanocomposite sample decreased as the average field increased. These observations suggest that, instead of the MgO nanofiller suppressing the electronic avalanche, it suppresses the conduction current, which was determined by the space charge, leading to the higher DC breakdown strength. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]


    Intracellular Distribution of Macrophage Targeting Ferritin,Iron Oxide Nanocomposite

    ADVANCED MATERIALS, Issue 4 2009
    Masaki Uchida
    Intracellular distribution of iron oxide nanoparticles incorporated within a ferritin mutant that displays genetically introduced cell-targeted peptides (RGD-4C) on its exterior surface are investigated using scanning transmission electron microscopy with a high-angle annular dark-field detector. The particles (indicated by arrows) internalized into macrophages much more effectively than those with noncell-targeted ferritin. [source]


    New Microshaping Concepts for Ceramic/Polymer Nanocomposite and Nanoceramic Fibers

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010
    Yoram De Hazan
    New, general, and versatile concepts for the fabrication of continuous ceramic and ceramic/polymer nanocomposite fibers have been developed. These enable the fabrication of new ceramic and highly loaded nanocomposite fibers with controlled compositions and microstructures. Continuous fibers with dimensions of 15,500 ,m have been demonstrated using several spinning approaches. [source]


    Spark Plasma Sintering of an Infrared-Transparent Y2O3,MgO Nanocomposite

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2010
    DongTao Jiang
    A novel optically transparent ceramic nanocomposite Y2O3,MgO was produced using spark plasma sintering technique. Sintering parameters was optimized to obtain fully dense material while maintaining nanoscale grain size. The sintered nanocomposite has an excellent infrared transmission as a result of small grain size and homogeneous microstructure. Postsinter annealing can significantly improve the transmission. Overly larger grain size severely degrades the transmittance. [source]


    Fractographic Montage for a Si3N4,SiC Nanocomposite

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2006
    Monika Ka, iarovį
    A silicon nitride,silicon carbide nanocomposite has been prepared by an in situ method that utilizes C+SiO2 carbo-thermal reduction during the sintering process. The materials consist of a silicon nitride matrix, with an average grain size of 140 nm, and inter- and intragranular SiC particles with sizes of approximately 250 and 45 nm, respectively. The four-point bending strength and its distribution were investigated. The fracture origins were identified and characterized using fractographic methods, and a fractographic montage of the Weibull plot and fracture origins was constructed. The fracture origins were subsurface and volume located processing defects with sizes from 5 to 460 ,m, mainly in the form of clusters of pores, together with clusters of large SiC grains. [source]


    Preparation of a Highly Conductive Al2O3/TiN Interlayer Nanocomposite through Selective Matrix Grain Growth

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2006
    Xihai Jin
    An electroconductive TiN/Al2O3 nanocomposite was prepared by a selective matrix grain growth method, using a powder mixture of submicrosized ,-Al2O3, nanosized ,-Al2O3, and TiN nanoparticles synthesized through an in situ nitridation process. During sintering, a self-concentration of TiN nanoparticles at the matrix grain boundary occurred, as a result of the selective growth of large ,-Al2O3 matrix grains. Under suitable sintering conditions, a typical interlayer nanostructure with a continuous nanosized TiN interlayer was formed along the Al2O3 matrix grain boundary, and the electroconducting behavior of the material was significantly improved. Twelve volume percent TiN/Al2O3 nanocomposite with such an interlayer nanostructure showed an unprecedentedly low resistivity of 8 × 10,3,·cm, which was more than two orders lower than the TiN/Al2O3 nanocomposite without such an interlayer nanostructure. [source]


    Electrostatic Self-Assembly of a Pt-around-Au Nanocomposite with High Activity towards Formic Acid Oxidation,

    ANGEWANDTE CHEMIE, Issue 12 2010
    Sheng Zhang
    Gegensätze ziehen sich an: ,Pt-auf-Au"-Nanokomposite entstehen durch elektrostatische Selbstorganisation (siehe Bild; PDDA=Poly(diallyldimethylammoniumchlorid)) und sind in der Oxidation von Ameisensäure viel aktiver als reine Pt-Katalysatoren. Ein möglicher Grund hierfür ist der effiziente HCOO-Übertritt vom Au- auf die umgebenden Pt-Nanopartikel, wo HCOO zu CO2 weiteroxidiert wird. [source]


    Fe3O4 Core/Layered Double Hydroxide Shell Nanocomposite: Versatile Magnetic Matrix for Anionic Functional Materials,

    ANGEWANDTE CHEMIE, Issue 32 2009
    Liang Li Prof.
    Funktionelle Umhüllung: Das im Titel genannte Nanokomposit zeigt eine hohe Kapazität für die Beladung mit Anionen wie dem katalytisch aktiven W7O246,. Die Methode (siehe Schema; LDH=schichtförmiges Doppelhydroxid) bietet einen allgemeinen Zugang zur einfachen und direkten Herstellung von Kern-Schale-Strukturen mit magnetischen Kernen und verschiedenartig funktionalisierten Schalen. [source]


    Sol-gel Preparation of CNT/ZnO Nanocomposite and Its Photocatalytic Property

    CHINESE JOURNAL OF CHEMISTRY, Issue 7 2009
    Xuejing WANG
    Abstract Using carbon nanotubes (CNT) as templete, CNT/ZnO nanocomposite was prepared by a sol-gel method. Its structure was characterized by XRD, IR and TEM. The UV absorbing properties were detected by a UV spectrophotometer. Photo degradation of methyl red in aqueous solution was investigated by using CNT/ZnO nanocomposite as photocatalyst. The results showed that the nanocomposite was composed of carbon nanotubes coated evenly by ZnO particles, with a diameter of 50,60 nm. UV-vis spectra indicated that the as-prepared CNT/ZnO nanocomposite had absorption of visible light as well as ultraviolet light. 60% CNT-added nanocomposite had the highest degradation rate for methyl red under the sunlight irradiation. [source]


    Direct Electrochemistry of Hemoglobin Immobilized on Colloidal Gold-Hydroxyapatite Nanocomposite for Electrocatalytic Detection of Hydrogen Peroxide

    ELECTROANALYSIS, Issue 2 2009
    Juan You
    Abstract A novel nanocomposite of colloidal gold (GNPs) and hydroxyapatite nanotubes (Hap) was prepared for immobilization of a redox protein, hemoglobin (Hb), on glassy carbon electrode. The immobilized Hb showed fast direct electron transfer and excellent electrocatalytic behavior toward reduction of hydrogen peroxide. A synergic effect between GNPs and Hap for accelerating the surface electron transfer of Hb was observed, which led to a pair of redox peaks with a formal potential of (,340±2) mV at pH,7.0, and a new biosensor for hydrogen peroxide with a linear range from 0.5 to 25,,M and a limit of detection of 0.2,,M at 3,. Owing to the good biocompatibility of the nanocomposite, the biosensor exhibited good stability and acceptable reproducibility. The as-prepared nanocomposite film provided a good matrix for protein immobilization and biosensor preparation. [source]


    Synthesis and Characterization of MWNTs/Au NPs/HS(CH2)6Fc Nanocomposite: Application to Electrochemical Determination of Ascorbic Acid

    ELECTROANALYSIS, Issue 16 2008
    Jian-Ding Qiu
    Abstract In this article, a detailed electrochemical study of a novel 6-ferrocenylhexanethiol (HS(CH2)6Fc) self-assembled multiwalled carbon nanotubes-Au nanoparticles (MWNTs/Au NPs) composite film was demonstrated. MWNTs/Au NPs were prepared by one-step in situ synthesis using linear polyethyleneimine (PEI) as bifunctionalizing agent. HS(CH2)6Fc, which acted as the redox mediator, was self-assembled to MWNTs/Au NPs via Au-S bond. Transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier transformed infrared absorption spectroscopy (FT-IR), UV-visible absorption spectroscopy, and cyclic voltammetry were used to characterize the properties of the MWNTs/Au NPs/HS(CH2)6Fc nanocomposite. The preparation of the nanocomposite was very simple and effectively prevented the leakage of the HS(CH2)6Fc mediator during measurements. The electrooxidation of AA could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique performance of MWNTs/Au NPs. The nanocomposite modified electrode exhibited excellent catalytic efficiency, high sensitivity, good stability, fast response (within 3,s) and low detection limit toward the oxidation of AA at a lower potential. [source]


    Therapeutic Window for Bioactive Nanocomposites Fabricated by Laser Ablation in Polymer-Doped Organic Liquids,

    ADVANCED ENGINEERING MATERIALS, Issue 5 2010
    Anne Hahn
    Abstract Polymeric nanomaterials are gaining increased interest in medical applications due to the sustained release of bioactive agents. Within this study nanomaterials are fabricated using laser ablation of silver and copper in polymer-doped organic liquids thus allowing to produce customized drug release systems. A strategy is shown to determine the therapeutic window for cells relevant for cochlear implant electrodes, defined by the viability of L929 fibroblasts, PC12 neuronal cells, and spiral ganglion cells on different concentrations of silver and copper ions. The distribution of nanoparticles within the silicone polymer matrix is determined using transmission electron microscopy. Hexane doped with 1% silicone resin is found to be an appropriate liquid matrix to fabricate a nanocomposite with a constant ion release rate. Silver ions of 10,µmol L,1 or copper ions of 100,µmol L,1 cause a suppression of tissue growth without inhibiting neuronal cell growth. The copper nanoparticle content of 0.1,wt% of the silicone composite releases ion concentrations which fit the therapeutic window. [source]


    Neurite Outgrowth on Nanocomposite Scaffolds Synthesized from PLGA and Carboxylated Carbon Nanotubes,

    ADVANCED ENGINEERING MATERIALS, Issue 12 2009
    Hyun Jung Lee
    Abstract Carbon nanotubes (CNTs) have been suggested as suitable materials for biomedical applications, especially in the neural area. It is essential not only to investigate the biocompatibility of CNTs with the neural system but also to determine proper methods for applying CNTs to neuronal growth. This work represents the first application of CNTs by electrospun poly(D,L -lactic-co-glycolic acid) (PLGA) scaffolds for a neural system. We synthesized electrospun nanocomposites of PLGA and single-walled carbon nanotubes functionalized by carboxylic acid groups (c- SWNTs), and investigated neurite outgrowth from SH-SY5Y cells on these nanocomposites as compared to that on fibrous PLGA alone. Cells on our PLGA/c -SWNT nanocomposite showed significantly enhanced mitochondrial function and neurite outgrowth compared to cells on PLGA alone. We concluded that c -SWNTs incorporated into fibrous PLGA scaffolds exerted a positive role on the health of neural cells. [source]


    Size and Geometry Effects on Flow Stress in Bioinspired de novo Metal-matrix Nanocomposites,

    ADVANCED ENGINEERING MATERIALS, Issue 10 2009
    Dipanjan Sen
    The figure shows a centrosymmetry analysis of the dislocation and defect structure in the metallic nanocomposite as obtained from molecular dynamics simulations, emphasizing the slipped regions during initial plasticity. The black region depicts the location of the hard platelet embedded in a soft matrix. [source]


    High-Performance Carbon-LiMnPO4 Nanocomposite Cathode for Lithium Batteries

    ADVANCED FUNCTIONAL MATERIALS, Issue 19 2010
    Seung-Min Oh
    Abstract A cathode material of an electrically conducting carbon-LiMnPO4 nanocomposite is synthesized by ultrasonic spray pyrolysis followed by ball milling. The effect of the carbon content on the physicochemical and electrochemical properties of this material is extensively studied. A LiMnPO4 electrode with 30 wt% acetylene black (AB) carbon exhibits an excellent rate capability and good cycle life in cell tests at 55 and 25 °C. This electrode delivers a discharge capacity of 158 mAh g,1 at 1/20 C, 126 mAh g,1 at 1 C, and 107 mAh g,1 at 2 C rate, which are the highest capacities reported so far for this type of electrode. Transmission electron microscopy and Mn dissolution results confirm that the carbon particles surrounding the LiMnPO4 protect the electrode from HF attack, and thus lead to a reduction of the Mn dissolution that usually occurs with this electrode. The improved electrochemical properties of the C-LiMnPO4 electrode are also verified by electrochemical impedance spectroscopy. [source]


    Magnetically Controllable Silver Nanocomposite with Multifunctional Phosphotriazine Matrix and High Antimicrobial Activity

    ADVANCED FUNCTIONAL MATERIALS, Issue 14 2010
    Panagiotis Dallas
    Abstract A recently developed multi-functional phosphotriazine-based polymer is used as a matrix for embedding ,-Fe2O3 nanoparticles as well as a suitable chemical template for surface modification with silver nanoparticles. For the primary magnetic modification, maghemite nanoparticles are surface modified with oleic acid in order to render them organophilic and to prevent the aggregation of the nanoparticles. This aggregation could occur as the polymer synthesis, based on reaction of phosphonitrilic chlorine and 1,4-phenylenediamine, takes place in toluene. The surface active amine units of the polymer structure enable the reduction of silver cations to silver nanoparticles, which are well attached and finely dispersed on its surface. The developed nanocomposite represents one of the few magnetically controllable antibacterial agents based on silver nanoparticles. Magnetic measurements reveal the completely suppressed interactions among maghemite nanoparticles because of their perfect surface coating with an organic surfactant and fine dispersion inside the polymer matrix. This magnetic nanocomposite exhibits a high antibacterial and antifungal activity as proven by tests with nine bacterial strains and four candida (yeast genus) species. For the majority of the tested species, the minimum-inhibition concentrations are below 100,mg,L,1, which is comparable to their equivalent minimum-inhibition concentrations in colloidal silver systems. [source]


    Designed Multifunctional Nanocomposites for Biomedical Applications

    ADVANCED FUNCTIONAL MATERIALS, Issue 10 2010
    Humphrey H. P. Yiu
    Abstract The assembly of multifunctional nanocomposite materials is demonstrated by exploiting the molecular sieving property of SBA-16 nanoporous silica and using it as a template material. The cages of the pore networks are used to host iron oxide magnetic nanoparticles, leaving a pore volume of 0.29,cm3,g,1 accessible for drug storage. This iron oxide,silica nanocomposite is then functionalized with amine groups. Finally the outside of the particle is decorated with antibodies. Since the size of many protein molecules, including that of antibodies, is too large to enter the pore system of SBA-16, the amine groups inside the pores are preserved for drug binding. This is proven using a fluorescent protein, fluorescein-isothiocyanate-labeled bovine serum albumin (FITC-BSA), with the unreacted amine groups inside the pores dyed with rhodamine B isothiocyanate (RITC). The resulting nanocomposite material offers a dual-targeting drug delivery mechanism, i.e., magnetic and antibody-targeting, while the functionalization approach is extendable to other applications, e.g., fluorescence,magnetic dual-imaging diagnosis. [source]


    A flammability performance comparison between synthetic and natural clays in polystyrene nanocomposites

    FIRE AND MATERIALS, Issue 4 2005
    Alexander B. Morgan
    Abstract Polymer-clay nanocomposites are a newer class of flame retardant materials of interest due to their balance of mechanical, thermal and flammability properties. Much more work has been done with natural clays than with synthetic clays for nanocomposite flammability applications. There are advantages and disadvantages to both natural and synthetic clay use in a nanocomposite, and some of these, both fundamental and practical, will be discussed in this paper. To compare natural and synthetic clays in regards to polymer flammability, two clays were used. The natural clay was a US mined and refined montmorillonite, while the synthetic clay was a fluorinated synthetic mica. These two clays were used as inorganic clays for control experiments in polystyrene, and then converted into an organoclay by ion exchange with an alkyl ammonium salt. The organoclays were used to synthesize polystyrene nanocomposites by melt compounding. Each of the formulations was analysed by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Flammability performance was measured by cone calorimeter. The data from the experiments show that the synthetic clay does slightly better at reducing the heat release rate (HRR) than the natural clay. However, all the samples, including the inorganic clay polystyrene microcomposites, showed a decreased time to ignition, with the actual nanocomposites showing the most marked decrease. The reason for this is postulated to be related to the thermal instability of the organoclay (via the quaternary alkyl ammonium). An additional experiment using a more thermally stable organoclay showed a time to ignition identical to that of the base polymer. Finally, it was shown that while polymer-clay nanocomposites (either synthetic or natural clay based) greatly reduce the HRR of a material, making it more fire safe, they do not provide ignition resistance by themselves, at least, at practical loadings. Specifically, the cone calorimeter HRR curve data appear to support that these nanocomposites continue to burn once ignited, rather than self-extinguish. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Ultrafast Photonics: Graphene,Polymer Nanofiber Membrane for Ultrafast Photonics (Adv. Funct.

    ADVANCED FUNCTIONAL MATERIALS, Issue 5 2010
    Mater.
    Loh and co-workers demonstrate on page 782 an electrospun graphene,polymer nanocomposite that exhibits wideband saturable absorbance for laser pulse shaping. A freestanding, mechanically robust membrane which is composed of nanofiber network of graphene-polymer nanocomposite is fabricated by electrospinning and applied as a mode locker in fiber lasers. The performance of these graphene-polymer nanocomposites is better than single-wall carbon nanotubes in terms of modulation depth and nonsaturable loss. [source]


    Graphene,Polymer Nanofiber Membrane for Ultrafast Photonics

    ADVANCED FUNCTIONAL MATERIALS, Issue 5 2010
    Qiaoliang Bao
    Abstract A freestanding membrane composed of a nanofiber network of a graphene,polymer nanocomposite is fabricated by electrospinning and applied as an optical element in fiber lasers. The functionalization of graphene with conjugated organic molecules provides a handle for improving mechanical and thermal properties as well as tuning the optical properties. A small loading (0.07,wt%) of functionalized graphene enhances the total optical absorption of poly(vinyl acetate) (PVAc) by 10 times. The electrospun graphene,polymer nanocomposites exhibit wideband saturable absorbance for laser pulse shaping, and attain a larger modulation depth and smaller nonsaturable loss than single-walled carbon nanotubes. The results show that electrospun graphene nanocomposites are promising candidates as practical and efficient photonic materials for the generation of ultrashort pulses in fiber lasers. [source]


    Vertically Aligned Nanocomposite Thin Films as a Cathode/Electrolyte Interface Layer for Thin-Film Solid Oxide Fuel Cells

    ADVANCED FUNCTIONAL MATERIALS, Issue 24 2009
    Jongsik Yoon
    Abstract A thin layer of a vertically aligned nanocomposite (VAN) structure is deposited between the electrolyte, Ce0.9Gd0.1O1.95 (CGO), and the thin-film cathode layer, La0.5Sr0.5CoO3 (LSCO), of a thin-film solid-oxide fuel cell (TFSOFC). The self-assembled VAN nanostructure contains highly ordered alternating vertical columns of CGO and LSCO formed through a one-step thin-film deposition process that uses pulsed laser deposition. The VAN structure significantly improves the overall performance of the TFSOFC by increasing the interfacial area between the electrolyte and cathode. Low cathode polarization resistances of 9,×,10,4 and 2.39,, were measured for the cells with the VAN interlayer at 600 and 400,°C, respectively. Furthermore, anode-supported single cells with LSCO/CGO VAN interlayer demonstrate maximum power densities of 329, 546, 718, and 812,mW cm,2 at 550, 600, 650, and 700,°C, respectively, with an open-circuit voltage (OCV) of 1.13,V at 550,°C. The cells with the interlayer triple the overall power output at 650,°C compared to that achieved with the cells without an interlayer. The binary VAN interlayer could also act as a transition layer that improves adhesion and relieves both thermal stress and lattice strain between the cathode and the electrolyte. [source]