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Silver Nanoparticles (silver + nanoparticle)

Distribution by Scientific Domains

Polymers and Materials Science	55%
Chemistry	31%
Physics and Astronomy	10%

Distribution within Polymers and Materials Science

Polymer Science & Technology General	43%
General & Introductory Materials Science	32%

Selected Abstracts

Electrodeposited Silver Nanoparticles on Carbon Ionic Liquid Electrode for Electrocatalytic Sensing of Hydrogen Peroxide

ELECTROANALYSIS, Issue 13 2009
Afsaneh Safavi
Abstract Silver nanoparticles (narrowly dispersed in diameter) were electrodeposited on carbon ionic liquid electrode (CILE) surface using a two-step potentiostatic method. Potentiostatic double pulse technique was used as a suitable and simple method for controlling the size and morphologies of silver nanoparticles electrodeposited on CILE. The obtained silver nanoparticles deposited on CILE surface showed excellent electrocatalytic activity (low overpotential of ,0.35,V vs. Ag/AgCl) towards reduction of hydrogen peroxide. A linear dynamic range of 2,200,,M with an experimental detection limit of 0.7,,M (S/N=3) and reproducibility of 4.1% (n=5) make the constructed sensor suitable for peroxide determination in aqueous solutions. [source]

Preparation of Novel Arrays Silver Nanoparticles Modified Polyrutin Coat-Paraffin-Impregnated Graphite Electrode for Tyrosine and Tryptophan's Oxidation

ELECTROANALYSIS, Issue 8 2008
Guan-Ping Jin
Abstract A novel array silver nanoparticles and Rutin complex film modified paraffin-impregnated graphite electrode was proposed in this work (denoted as Ag/Rutin/WGE). The characteristics were investigated by the field emission scanning electron microscopy (FE-SEM), infrared spectra (IR), UV-visible (UV), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. Silver ions were gradually chelated by polyrutin film at 4,-oxo-5,-OH and 5-OH-4-oxo sites accompanying adsorption, then. Silver nanoparticles were highly-dispersed electrodeposited on polyrutin film. The electrochemical behaviors of tyrosine (Tyr) and tryptophan (Trp) were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The Ag/Rutin/WGE electrode shows overlapping catalysis for the oxidation of Tyr and Trp. The linear response of Tyr and Trp were 0.3,10.0 and 0.7,70.0,,M with detection limit of 0.07 and 0.1,,M in a signal-to-noise ratio of 3. [source]

Thermosensitive Nanostructures Comprising Gold Nanoparticles Grafted with Block Copolymers,

ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007
D. Li
Abstract Binary thermosensitive nanocomposites are fabricated by grafting block copolymers of poly(N -isopropylacrylamide) and poly(methoxy-oligo(ethylene glycol) methacrylate) onto gold nanoparticles through consecutive, surface-initiated, atom-transfer radical polymerization (ATRP). These Au@copolymer nanocomposites display a well-defined core/shell nanostructure and have two thermosensitive points near 33 and 55,°C in an aqueous suspension corresponding to the thermally induced conformational transition of inner homopolymer segments and outer oligo(ethylene glycol)-containing copolymer layer, respectively. Silver nanoparticles trapped within Au@copolymer nanocomposites with weakly crosslinked shells display thermally modulated catalytic activity as heterogeneous catalysts because of the thermosensitive collapse of the polymer layers. [source]

Fabrication of high-performance, gradient-refractive-index plastic rods with surfmer-cluster-stabilized nanoparticles

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2006
Jui-Hsiang Liu
Abstract A novel method was developed with surfmer-cluster-stabilized silver nanoparticles to prepare high-performance, gradient-refractive-index (GRIN) plastic rods based on methyl methacrylate. To fabricate the GRIN plastic rods, a novel polymerizable surfactant (surfmer) of 4-(11-acryloxyundecyloxy)benzoic acid (AUBA) was synthesized. Silver nanoparticles were prepared with a reverse micelle method in the presence of the novel surfmer. During the fabrication of the silver nanoparticles, the sodium salt of AUBA was formed. GRIN plastic rods were fabricated through centrifugal polymerization and then were heat-treated at 100 °C under 0.1 Torr for 24 h to remove residual monomers and water. The distribution of the surfmer-cluster-stabilized nanoparticles inside the plastic rods was studied with transmission electron microscopy (TEM). The real-image transmission through the fabricated rods was also confirmed. The results obtained in this investigation suggested that the control of the distribution of surfmer-cluster-stabilized nanoparticles could be used to fabricate GRIN rods. Furthermore, the existence of the crosslink-like surfmers increased the thermal stability of the plastic rods. The GRIN distribution of the rods was established by the dispersion of nanoparticles inside the plastic rods through TEM analysis, refractive-index analysis, and real-image transmission. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5933,5942, 2006 [source]

Antibiotic glass slide coated with silver nanoparticles and its antimicrobial capabilities

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11 2008
Yaohui Lv
Abstract Silver nanoparticles were covalently coated on a glass surface by overnight exposure of the glass substrate to nanoparticle solutions, using 3-aminopropyltriethoxysilane (APTES) as a coupling agent. Washing and air-drying yield a uniformly coated glass substrate, which can be used as a material capable of killing harmful microorganisms in food industry. Nanoparticles are stable on the glass surface and are not washed away by water; they even remain on the glass surface under short-term ultrasonic irradiation. The morphology of silver nanoparticles on the glass substrate was characterized by scanning electron microscope (SEM). The existence of Ag nanoparticles on the substrate was also confirmed by ultraviolet-visible (UV,Vis) spectroscopy. Fourier transform infrared (FT-IR) measurement shows that the connection is based on covalent bonds between silver nanoparticle surface/APTES molecules. Combining the effects of low cost and effectiveness in prohibiting the growth of Escherichia coli, such materials are expected to be used as antibacterial coatings, which may have large potential applications in food industry. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Anisotropy in optical transmittance and molecular chain orientation of silver- dispersed uniaxially drawn polyimide films

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2003
Sho-ichi Matsuda
Abstract The anisotropy in optical transmittance in the visible and near-infrared region observed for uniaxially drawn and silver-dispersed polyimide (PI) films was investigated. The films were prepared in a one-step operation that consists of thermal curing and simultaneous uniaxial drawing of poly(amic acid) (PAA) films dissolving 5.7,,,20 mol% of silver nitrate. The PAA was converted to PI by heating, and the PI chains were orientated along the drawing direction during curing. Silver nanoparticles were precipitated in the films when they were cured in air and under nitrogen. In particular, silver nanoparticles aggregated along drawing direction and spheroidal nanoparticles (size of longer axis: 10,25,nm, aspect ratio: ca. 1.5) were observed in the films cured in air, and distinct anisotropy in optical transmittance was observed. The maximum optical anisotropy was obtained with a specific holding time at the final curing temperature (320,°C). In addition, the anisotropy can be controlled by polymer chain orientation when films are cured with the optimal holding time. In optimized preparing conditions, anisotropies in transmittance larger than 500,:,1 were obtained at the wavelengths between 700 and 900,nm, and its optical properties were retained after annealing at 150,°C for 1,hr. The PI films thus obtained can be used as thermally stable thin-film polarizers. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Protein adsorption drastically reduces surface-enhanced Raman signal of dye molecules

JOURNAL OF RAMAN SPECTROSCOPY, Issue 9 2010
Dongmao Zhang
Abstract There is an increasing interest in developing surface enhancement Raman spectroscopy methods for intracellular biomolecule and for in vitro protein detection that involve dye or protein,dye conjugates. In this work, we have demonstrated that protein adsorption on silver nanoparticle (AgNP) can significantly attenuate the surface-enhanced Raman spectroscopy (SERS) signal of dye molecules in both protein/dye mixtures and protein/dye conjugates. SERS spectra of 12 protein/dye mixtures were acquired using 4 proteins [bovine serum albumin (BSA), lysozyme, trypsin, and concanavalin A] and three dyes [Rhodamine 6G, adenine, and fluorescein isothiocyanate (FITC)]. Besides the protein/dye mixtures, spectra were also obtained for the free dyes and four FITC-conjugated proteins. While no SERS signal was observed in protein/FITC mixtures or conjugates, a significantly reduced SERS intensity (up to 3 orders of magnitude) was observed for both R6G and adenine in their respective protein mixtures. Quantitative estimation of the number of dye molecules absorbed onto AgNP implied that the degree of R6G SERS signal reduction in the R6G/BSA sample is 2 to 3 orders of magnitude higher than what could be accounted for by the difference in the amount of the absorbed dyes. This finding has significant implications for both intracellular SERS analyses and in vitro protein detection using SERS tagging strategies that rely on Raman dyes as reporter molecules. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Nanocomposites of silver nanoparticle and dinonylnaphthalene disulfonic acid-doped thermoreversible polyaniline gel

POLYMER ENGINEERING & SCIENCE, Issue 3 2010
Ashesh Garai
Silver/polyaniline-dinonylnaphthalene disulfonic acid (PANI-DNNDSA) gel nanocomposites are prepared from the reduction of silver salt by polyaniline in formic acid medium. Scanning electron micrographs (SEM) indicate the presence of three-dimensional fibrillar network structure and the silver nanoparticles remain dispersed within the PANI-DNNDSA fibrillar network. Differential scanning calorimetric (DSC) study shows reversible first-order phase transition characterizing the composite to behave as a thermoreversible gel. Transmission electron micrographs (TEM) show a decrease of nanoparticle size with increasing AgNO3 concentration. Wide angle X-ray scattering (WAXS) patterns show lamellar structure in the gel as well as in the gel metal nanocomposites (GMNCs) and the two melting peaks in the DSC patterns correspond to the melting of monolayer and bilayer crystals produced from the interdigitation of DNNDSA tails anchored from PANI chains within the PANI lamella. The above melting points are greater in the GMNCs than that of pure gel indicating the formation of complex melting thermogram with crystallites produced from the anchored surfactants tails at the surface of Ag nanoparticles. The GMNCs show a higher thermal stability than that of pure PANI-DNNDSA gel. PANI-DNNDSA gel has an emission peak at 354 nm but fluorescence quenching occurs in the GMNCs and the emission peak becomes red shifted. Also in the UV,vis spectra the , band-polaron band transition peak shows a red shift and the DC conductivity increases with increasing Ag nanoparticle concentration in the GMNCs. The current (I),voltage (V) characteristic curves indicate Ohmic nature of conductivity of the gel and the current at the same voltage increases appreciably with increasing Ag nanoparticle concentration. These GMNCs are easily processible due to its thermoreversible nature. So, an easily processible, thermally stable and highly conducting DNNDSA-doped PANI-Ag gel nanocomposite with interesting photoluminescent property has been successfully developed suitable for optoelectronic applications. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source]

Synthesis and characterization of polyaniline derivative and silver nanoparticle composites

POLYMER INTERNATIONAL, Issue 10 2008
Gururaj M Neelgund
Abstract BACKGROUND: There has been a recent surge of interest in the synthesis and applications of electroactive polymers with incorporated metal nanoparticles. These hybrid systems are expected to display synergistic properties between the conjugated polymers and the metal nanoparticles, making them potential candidates for applications in sensors and electronic devices. RESULTS: Composites of polyaniline derivatives,polyaniline, poly(2,5-dimethoxyaniline) and poly(aniline-2,5-dimethoxyaniline),and silver nanoparticles were prepared through simultaneous polymerization of aniline derivative and reduction of AgNO3 in the presence of poly(styrene sulfonic acid) (PSS). We used AgNO3 as one of the initial components (1) to form the silver nanoparticles and (2) as an oxidizing agent for initiation of the polymerization reaction. UV-visible spectra of the synthesized nanocomposites reveal the synchronized formation of silver nanoparticles and polymer matrix. The morphology of the silver nanoparticles and degree of their dispersion in the nanocomposites were characterized by transmission electron microscopy. Thermogravimetric analysis and differential scanning calorimetry results indicate an enhancement of the thermal stability of the nanocomposites compared to the pure polymers. The electrical conductivity of the nanocomposites is in the range 10,4 to 10,2 S cm,1. CONCLUSION: A single-step process for the synthesis of silver nanoparticle,polyaniline derivative nanocomposites doped with PSS has been demonstrated. The approach in which silver nanoparticles are formed simultaneously during the polymerization process results in a good dispersion of the nanoparticles in the conductive polymer matrix. Copyright © 2008 Society of Chemical Industry [source]

Green Synthesis of Silver Nanoparticles Using Ionic Liquid and Application for the Detection of Dissolved Oxygen

ELECTROANALYSIS, Issue 6 2010
Tsung-Hsuan Tsai
Abstract The electrochemical synthesis of silver nanoparticles (nano-Ag) has been successfully carried out on glassy carbon electrode (GCE) and indium tin oxide electrode (ITO) using 1-butyl-3-methylimidazolium tetrafluoroborate (BMT) as green electrolytes. Further the electrodeposited nano-Ag modified ITO electrode has been examined using atomic force microscopy (AFM), and X-ray diffraction studies (XRD). The electrodeposited Ag nanoparticles on ITO were found in the size range of 5 to 35,nm. The nano-Ag film modified GCE was further coated with nafion (Nf) and BMT (1,:,1 ratio) mixture and found to be stable in BMT and in pH,7 phosphate buffer solution (PBS). The nano-Ag/BMT-Nf film modified GCE successfully applied for the oxygen reduction reaction in neutral pH (pH,7.0 PBS). The proposed film modified GCE successfully reduces the over potential and show well defined reduction peaks for the detection of dissolved oxygen using cyclic voltammetry (CV) and rotating disc voltammetry (RDE). The film also applied for the detection of dissolved oxygen using electrochemical impedance spectroscopic studies (EIS). [source]

Electrodeposited Silver Nanoparticles on Carbon Ionic Liquid Electrode for Electrocatalytic Sensing of Hydrogen Peroxide

Preparation of Novel Arrays Silver Nanoparticles Modified Polyrutin Coat-Paraffin-Impregnated Graphite Electrode for Tyrosine and Tryptophan's Oxidation

Growth of Metal Nanoparticles in a Sol-Gel Silica Thin Film

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2007
Miroslava Malenovska
Abstract Silica films on glass substrates with homogeneously dispersed platinum, gold or silver nanoparticles were prepared by sol-gel processing mixtures of tetraethoxysilane and {3-[(2-aminoethyl)amino]propyl}triethoxysilane complexes of the corresponding metal ions, followed by dip-coating and hydrogen treatment of the films at elevated temperatures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Pattern Formation of Silver Nanoparticles in 1-, 2-, and 3D Microstructures Fabricated by a Photo- and Thermal Reduction Method

ADVANCED FUNCTIONAL MATERIALS, Issue 14 2010
Jong-Jin Park
Abstract One-, two-, and three-dimensional microstructures with dispersed silver nanoparticles are fabricated by a combination of photopatterning and thermal treatment from a silver salt containing photosensitive epoxy resin. Ultraviolet photo-irradiation and subsequent thermal treatment are combined to control the rate of silver salt reduction, the size and the arrangement of nanoparticles, as well as the reticulation of the epoxy resin. This approach allows the creation of high resolution 1-, 2-, and 3D patterns containing silver nanoparticles, with a homogeneous distribution of nanoparticles regardless of the irradiated area. [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]

Surface-Grafted Gel-Brush/Metal Nanoparticle Hybrids

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2010
Edmondo M. Benetti
Abstract Polymer brushes are classically defined and are to date employed as assemblies of macromolecules tethered at one end to a surface. The concept of preparing surface-grafted gels by crosslinking such brushes is attractive since it gives rise to new opportunities related to the constraints present in this type of structure. Aiming at the development of nanostructured films possessing precisely adjustable chemical, mechanical, and optical properties, the present article describes the preparation of novel grafted layers based on gel-brush/metal nanoparticle hybrids. These films were synthesized by surface-initiated atom transfer radical polymerization of hydroxyethyl methacrylate with a small percentage of a crosslinker. The swelling, morphological, and mechanical properties of the gel-brushes are shown to be highly dependent on the relative amount of crosslinker used. The gel-brushes are subsequently used as matrixes for the controlled synthesis of silver nanoparticles with overall characteristics that are specifically tunable as a function of the macromolecular structure of the brush template. [source]

Hydrophilic Sparse Ionic Monolayer-Protected Metal Nanoparticles: Highly Concentrated Nano-Au and Nano-Ag "Inks" that can be Sintered to Near-Bulk Conductivity at 150,°C

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2010
Bibin T. Anto
Here, monolayer-protected gold and silver nanoparticles with extremely high solvent dispersibility (over 200,mg mL,1 in water and glycols) and low coalescence temperature (approximately 150,°C, measured by the percolation transition temperature Tp) are developed, to reach conductivities better than 1,×,105,S cm,1. These materials are suitable for inkjet and other forms of printing on substrates that may be solvent- and/or temperature-sensitive, such as for plastic electronics, and as bus lines for solar and lighting panels. This is achieved using a new concept of the sparse ionic protection monolayer. The metal nanoparticles are initially protected by a two-component mixed ligand shell comprising an ,-functionalized ionic ligand and a labile ligand. These are selectively desorbed to give a sparse shell of the ,-ionic ligands of ca. 25% coverage. Through a systematic study of different monolayer-protected Au nanoparticles using FTIR spectroscopy, supported by XPS and DSC, it is shown that Tp is not determined by thermodynamic size melting or by surface area effects, as previously thought, but by the temperature when ca. 80% of the dense monolayer is eliminated. Therefore, Tp depends on the thermal stability and packing density of the shell, rather than the size of the metal core, while the solubility characteristics depend strongly on the exposed terminal group. [source]

Magnetic Multi-Functional Nano Composites for Environmental Applications

ADVANCED FUNCTIONAL MATERIALS, Issue 8 2009
Jie Dong
Abstract A novel concept is proposed to synthesize a new class of composites featuring magnetic, molecular sieve and metallic nanoparticle properties. These multi-functional materials have potential applications as recyclable catalysts, disinfectants and sorbents. The magnetic property enables effective separation of the spent composites from complex multiphase systems for regeneration and recycle, safe disposal of the waste and/or recovery of loaded valuable species. The zeolite molecular sieve provides a matrix which supports a remarkably new, simple, efficient and economical method to make stable, supported silver nanoparticles by silver ion exchange and controlled thermal reduction. The silver nanoparticles generated in this way have excellent properties such as high reactivity and good thermal stability without aggregation, which act as nano reactors for desired functionality in a wide range of applications. Magnetic component (Fe3O4), molecular sieve matrix (zeolite) and silver nanoparticles generated by ion exchange followed by controlled reduction, together form this unique novel composite with designed functions. It represents a practically operational, economical, sustainable and environmentally friendly new advanced functional material. This paper focuses on the novel synthesis and characterization of the composite, with an example of applications as sorbents for the removal of vapor-phase mercury from the flue gas of coal-fired power plants. [source]

Reactive Template Method to Synthesize Gold Nanoparticles with Controllable Size and Morphology Supported on Shells of Polymer Hollow Microspheres and Their Application for Aerobic Alcohol Oxidation in Water

ADVANCED FUNCTIONAL MATERIALS, Issue 7 2009
Jie Han
Abstract A novel method has been developed to synthesize gold nanoparticles with tunable size and morphology supported on both inner and outer surfaces of poly(o -phenylenediamine) (PoPD) hollow microspheres, which act as both reductant and template/stabilizer. The size of gold nanoparticles supported on shells of PoPD hollow microspheres can be tuned from 3 to 15,nm by changing the concentration of the gold source, HAuCl4. Gold nanorods supported on shells of PoPD hollow microspheres can also be fabricated by introducing a well-known seed-growth strategy. In addition, silver nanoparticles supported on shells of PoPD hollow microspheres can also be successfully fabricated using the same strategy, which indicates the diversity of this proposed method for polymer hollow microspheres supporting noble metal nanoparticles. The products are characterized by X-ray diffraction and contact angle analysis. Furthermore, the catalytic activity of the obtained PoPD-microsphere-supported gold nanoparticles for aerobic alcohol oxidation is investigated. The results demonstrate that such polymer-supported gold nanoparticles can be used as reusable catalysts with high catalytic activity for aerobic alcohol oxidation in water. [source]

UV-vis-Induced Vitrification of a Molecular Crystal,

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2007
T. Naito
Abstract A charge-transfer complex of 2,5-dimethyl- N,N,-dicyanoquinonediimine (DM) with silver (crystalline Ag(DM)2, defined as ,) is irreversibly transformed by UV-vis illumination. Depending on the illumination conditions, three new types of solids (defined as ,, ,, and ,) with different structural and physical properties are obtained and examined by a variety of analytical techniques, including solid-state, high-resolution, cross-polarization magic angle spinning (CP-MAS) 13C,NMR, elemental analysis (EA), mass spectrometry (MS), X-ray absorption fine structure (XAFS), and powder X-ray diffraction (XRD). The CP-MAS, EA, MS, and XAFS results indicate that compound , is a glass state of Ag(DM)2. The transformation from crystalline (,) to amorphous (,) solid Ag(DM)2 is an irreversible exothermic glass transition (glass-transition temperature 155.2,°C; ,H,=,,126.8,kJ,mol,1), which implies that the glass form is thermodynamically more stable than the crystalline form. Compound , (Ag(DM)1.5) consists of silver nanoparticles (diameter (7,±,2),nm ) dispersed in a glassy matrix of neutral DM molecules. The N,CN,Ag coordination bonds of the , form are not maintained in the , form. Decomposition of , by intense illumination results in a white solid (,), identified as being composed of silver nanoparticles (diameter (60,±,10),nm). Physical and spectroscopic (XAFS) measurements, together with XRD analysis, indicate that the silver nanoparticles in both , and , are crystalline with lattice parameters similar to bulk silver; however, the magnetic susceptibilities differ from bulk silver. [source]

Reversible Storage of Lithium in Silver-Coated Three-Dimensional Macroporous Silicon,

ADVANCED MATERIALS, Issue 20 2010
Yan Yu
Three-dimensional macroporous silicon (see image) was synthesized by a magnesiothermic reduction method as an anode material for lithium ion batteries. An improved lithium storage performance was obtained after coating silver nanoparticles on the surface of the silicon. The silver-coated 3D macroporous silicon shows promise as an anode material in lithium ion batteries. [source]

Conjugated Polyelectrolyte,Metal Nanoparticle Platforms for Optically Amplified DNA Detection

ADVANCED MATERIALS, Issue 5 2010
Yusong Wang
A conjugated polyelectrolyte (CPE)-silver nanoparticle platform for DNA-sensing applications is fabricated (see figure), which provides over 17-fold enhancement of dye emission intensity, as compared to the intrinsic dye emission observed atop a conventional glass surface. Examination of the distance-dependence amplification process reveals that the role of the silver nanoparticles is to increase the effective field experienced by the light-harvesting CPE, and the metal enhanced fluorescence of the CPE could be translated into higher dye signal intensities for the detection platform. [source]

Organic Nanowires: Connecting Organic Nanowires (Adv. Mater.

ADVANCED MATERIALS, Issue 47 2009
47/2009)
Single-crystal organic nanowires are destined to become essential components in near-future organic electronics, however, currently one of the main drawbacks preventing implementation is the difficulty of creating stable interconnections between the nanowires. On p. 4816, Ana Borras and co-workers present a universal and effective method of creating nanowire,nanowire and nanowire,metallic Ohmic connections. The inside cover image shows the connection of single-crystal metallo-phthalocyanine nanowires via silver nanoparticles. [source]

Hierarchically Ordered Topographic Patterns via Plasmonic Mask Photolithography

ADVANCED MATERIALS, Issue 19 2009
Woo Soo Kim
By employing a block copolymer to spatially organize silver nanoparticles, laser light can be concentrated via plasmon resonance to locally expose a photoresist. By subsequent development, this plasmonic lithography can provide deep subwavelength scale features. [source]

Molecular Imaging of Cancer Cells Using Plasmon-Resonant-Enhanced Third-Harmonic-Generation in Silver Nanoparticles,

ADVANCED MATERIALS, Issue 24 2007
S.-P. Tai
We demonstrate molecule-specific third-harmonic-generation (THG) microscopy by using silver nanoparticles as THG contrast agents. Through matching surface plasmon wavelength to THG wavelength, strong contrast can be provided by silver nanoparticles under THG microscopy. By conjugating anti-her2 antibodies with silver nanoparticles, the expression of the Her2/neu oncogene in the cancer cell membranes is successfully imaged under THG modality for the first time. [source]

Ink-jet Printing and Microwave Sintering of Conductive Silver Tracks,

ADVANCED MATERIALS, Issue 16 2006
J. Perelaer
Conductive silver tracks on a polyimide substrate (see figure) are prepared by using microwave radiation to sinter silver nanoparticles printed on the substrate. This method shortens the necessary sintering time dramatically and is independent of the substrate used. Since the polymer substrate is virtually transparent to microwave radiation, a negligible amount of energy is absorbed by the substrate, whereas the conducting silver nanoparticles, with a high dielectric loss factor, strongly absorb the microwaves. [source]

High-Dielectric-Constant Silver,Epoxy Composites as Embedded Dielectrics,

ADVANCED MATERIALS, Issue 14 2005
L. Qi
The incorporation of organic-coated silver nanoparticles into an epoxy matrix (see Figure, a,f represent increasing Ag content) results in a flexible 0-3 type nanocomposite with a strikingly high dielectric constant (greater than 300). The composite retains the flexibility and other mechanical properties of the polymer matrix, and may be useful in applications where capacitors are embedded into printed circuit boards. [source]

Preparation and characterization of polymer/multiwall carbon nanotube/nanoparticle nanocomposites and preparation of their metal complexes

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2010
Ahmad Nozad Golikand
Abstract Carbon nanotube-polymer nanocomposites were synthesized and characterized successfully. In this work, multiwall carbon nanotubes (MWCNT) were opened using HNO3/H2SO4 mixture and filled by metal nanoparticles such as silver nanoparticles through wet-chemistry method. The oxidized MWCNT were reacted subsequently with thionyl chloride, 1,6-diaminohexane, producing MWNT-amine functionalized. Then the MWCNT containing metal nanoparticles were used as a monomer with different weight percentages in melt polymerization with An and CNCl separately. Furthermore, the polyamide and polytriazine modified MWCNT were used for the preparation of metal ion complexes such as Fe+2 and La+3. The structures and properties of nanocomposites were evaluated by TEM, DSC, TGA, and FT-IR methods. The chelating behavior and sorption capacities of prepared nanocomposites were carried out by using some metal ions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Effects of silver nanoparticles on the dynamic crystallization and physical properties of syndiotactic polypropylene

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008
Dong Wook Chae
Abstract The effects of silver (Ag) nanoparticles on the physical properties of syndiotactic PP (sPP) were investigated concentrating on the isothermal melt crystallization behavior under shear. sPP with 5 wt % Ag nanoparticles presented higher crystallization temperature (Tc) and heat of crystallization (,Hc) than pure sPP. At 90°C, the Ag nanoparticles had little effect on the induction time of crystallization but a little increased the half-time (t1/2) for the crystallization. At 100°C, however, the induction time was decreased with increasing the Ag content and the t1/2 was decreased up to the Ag content of 0.5 wt %. DSC melting endotherms exhibited double melting peaks when crystallized at 90°C under shear but a single melting peak when crystallized at 100°C. The WAXD patterns exhibited that the presence of Ag nanoparticles did not produce any change in the crystal structure of sPP. The tensile strength of sPP is little changed up to the Ag content of 0.1 wt % but it was decreased with further addition. In addition, the introduction of less than 0.1 wt % Ag increased the elongation at break, but further addition decreased it abruptly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Syzygium cumini leaf and seed extract mediated biosynthesis of silver nanoparticles and their characterization

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2010
Vineet Kumar
Abstract BACKGROUND: Plant mediated synthesis of metallic nanoparticles has been studied and reported, however, to date, the biomolecules involved in the synthesis of metallic nanoparticles have not been characterized. This study was therefore undertaken to characterize the biomolecules of Syzygium cumini involved in the synthesis of silver nanoparticles. RESULTS: Synthesis kinetics and morphological characterization of silver nanoparticles (SNP) synthesized using leaf extract (LE) and seed extract (SE) as well as their polar (water) fractions from Syzygium cumini were compared. The polyphenols content and high performance liquid chromatography (HPLC) profile of different fractions revealed good correlation between size and synthesis rate of SNP. SE contains more polyphenols and biochemical constituents than LE and therefore, showed higher synthesis rate and bigger sized SNP. To analyse the nature of biomolecules involved in the synthesis of SNP, LE and SE were fractionated on a polarity basis by solvent,solvent partitioning. Only the water fractions of LE and SE showed potential for SNP synthesis. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis of SNP indicated that all fractions catalyze the synthesis of spherical nanoparticles. The average size of SNP synthesized by LE, leaf water fraction, SE and seed water fraction were 30, 29, 92, and 73 nm respectively. CONCLUSION: Results suggest that only highly polar soluble constituents are responsible for SNP synthesis. The size of SNP was found to be directly correlated with the amount of polyphenols as well as surfactants present in the reaction solution. Thus, the amount of polyphenols could be one of the crucial parameters determining the size and distribution of SNP. Copyright © 2010 Society of Chemical Industry [source]