Papers by Keyword: Silver Nanoparticle

Abstract: Polyvinyl alcohol (PVA) doped with Ag thin films were synthesized from aqueous solution via sol gel method. The nanoparticle of silver was synthesized by chemical reduction using hydrazine hydrate. PVA-Ag thin films were deposited on the glass substrate by spin coating technique. Samples were varied with different combinations of metals such as Ag-Co and Ag-Al. The solutions and the films were characterized by using XRD, UV-Visible spectroscopy, AFM and TEM. XRD analysis indicates the formation of the single crystal Ag, Co and Al nanoparticles laid on (111) lattice planes. The crystallite sizes decrease when Co and Al are added to the PVA-Ag. UV-Vis absorption spectra confirmed the formation of Ag nanoparticles in the PVA matrix and the resonance plasmon band located at 417, 421 and 429 nm. Surface roughness of PVA-Ag nanocomposite thin film increased with the addition of Co and Al. TEM images show the non-agglomerated spherical particles in all samples. The performance of the sensor has been fabricated using I-V measurement with and without incubated the sensor electrode into E. coli. The result shows PVA-Ag nanocomposite thin film performed the higher sensitivity.

Abstract: Large-scale silver nanoparticles with fine dispersion and narrow size distribution were synthesized by reducing silver nitrate with sodium borohydride and sodium citrate and using poly (vinylpyrrolidone) as an adsorption agent in the ethanol solution. The sintering behavior and electrical properties of silver nanoparticles treated with and without glutaric acid were studied. Morphology studies showed that the treated silver nanoparticles obviously agglomerated and began to sinter at 200 °C and the sintering temperature is higher at least 50 degrees than that of the untreated silver nanoparticles The treated silver nanoparticles as fillers of electronically conductive adhesives (ECAs) is more advantageous to the increase of the conductivity. Otherwise, only in the conditions of the appropriate sintering temperature and loading of silver nanoparticles, the high conductivity of the ECAs was obtained. The effect of the treated silver nanoparticles on the electrical properties contributes to the surface activation and sintering behavior.Keywords: Silver nanoparticle, Sintering Behavior, Surface treatment, Electrical property

Abstract: In this paper, silver nanostructures were synthesized via a solvothermal method by reducing silver nitrate with ethylene glycol in the presence of poly (vinylpyrrolidone) and using NaCl, MgCl₂, AlCl₃, FeCl₃, Fe₂(SO₄)₃ , NaOH, NaBr and Na₂S as reaction inhibitor, respectively. Characteristics of the as-prepared silver nanostructures were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-visible (UV-vis) absorption spectrum. It is found that the mixture of nanoparticles and nanorods and nanowires can be observed in the AlCl₃ and NaOH systems, the nanorods as main products can be obtained in the MgCl₂ and NaCl and Fe₂(SO₄)₃ systems, the large scale silver nanowires as main products can be obtained in the FeCl₃ and Na₂S systems, especially in the Na₂S system, silver nanowires are very long and curved. The results indicated the reasons of the effect of the reaction inhibitors on the morphologies of silver nanostructures depend on the solubility product constant of silver salt which formed with silver ion and inhibitor anion ion in the initial stage and the properties of metal cationic ion of inhibitor. The smaller solubility product constant of silver salt or the presence of Fe³⁺ or low valence metal ion greatly facilitate the formation of one-dimensional silver nanostructures, especially to nanowires.

Abstract: Uniform films of silver nanoparticles (Ag NPs) were fabricated by self-assembly on 3-aminopropyltriethoxysilane (APTES) and [3-(2-aminoethyl) aminopropyl] trimethoxysilane (AEAPTES) modified glass slides. A stable Ag NPs suspension was synthesized via the reduction of silver nitrate using sodium citrate. Bulk characteristics of Ag NPs in aqueous solution were carried out by measuring their absorption spectrum, morphology and particle shape using the UV-vis absorption spectroscopy and transmission electron microscopy (TEM), respectively. The average diameter of Ag NPs is about 50 nm. The coverage of adsorbed particles on the modified glasses was measured by scanning electron microscopic imaging (SEM). The SEM images indicate that the Ag NPs films on the glasses are uniform. It is supposed that the adsorption processes are mainly controlled by electrostatic interactions. The adsorption amount of Ag NPs on APTES modified glass slides is much more than the amount on AEAPTES modified glass slides.

Abstract: Silver nanoparticles (Ag NPs) thin film were fabricated by radio-frequency (RF) magnetron sputtering on the quartz substrates in different sputtering time, then covered with a layer of rubrene by means of thermal evaporation. The sputtering time for preparation of Ag NPs could be tuned to increase the spectral overlap between the emission spectra of rubrene and surface plasmon resonance spectra, so that the surface plasmon enhancement was improved. Using a Fluorescence spectrophotometer (FLS920), the photoluminescence (PL) intensity of the rubrene/Ag NPs thin film was up to 22 times higher than that as-deposited rubrene thin film. It is attributed to the energy transfer effect in the surface plasmon resonance coupling, the surface plasmons mediated emission, and light scattering.

Abstract: Antibacterial potential of metallic silver nanoparticles (AgNPs) is considered to be influenced by their size and stability. In this study, the stable AgNPs capped with poly (4-styrenesulfonic acid-co-maleic acid) or PSSMA were successfully synthesized by using a chemical reduction method. The PSSMA-stabilized AgNPs (PSSMA-AgNPs) were characterized and tested for antibacterial activity against eight bacterial strains. Transmission electron microscopic studies showed that PSSMA-AgNPs were monodisperse spherical particles with an average size of 5.21 nm. From bacterial growth curve studies, PSSMA-AgNPs exhibited an antibacterial effect on Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 6538p, Staphylococcus aureus ATCC 43300, Staphylococcus epidermidis ATCC 12228 and Bacillus subtilis ATCC 6633) and Gram-negative bacteria (Escherichia coli ATCC 25922, Enterobacter aerogenes ATCC 13048 and Pseudomonas aeruginosa ATCC 27853). Moreover, the Gram-negative bacteria were found to be more susceptible to the AgNPs.

Abstract: Metallic nanoparticles have received great attention from chemists, physicists, biologists and engineers who wish to use them for the development of a new generation of nanodevices. In the present Communication, a completely “green” chemistry method for producing silver nanoparticles is introduced. The process is simple, environmentally benign, and quite efficient. Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and ecofriendly reducing and capping agents. In particular, silver nanoparticles are proved to have potential antibacterial, antifungal and antiplasmodial and antimicrobial properties. The present study was aimed to identify the antiplasmodial activity of green synthesised silver nanoparticles (AgNPs) using aqueous extract of plant Euphorbia hirta against P.falciparum. Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by aqueous extract of plant to generate extremely stable silver nanoparticles in water. The bio-reduced silver nanoparticles were appropriately characterized by UV–vis spectrum, Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The formation of the AgNPs synthesized from the XRD spectrum compared with the standard confirmed spectrum of silver particles formed in the present experiments were in the form of nanocrystals, as evidenced by the peaks at 2θ values of =28.01°, 32.41°, 46.44°, 55.05° and 57.75°. The scanning electron micrograph (SEM) showed structures of spherical, cubic shape, and the size range was found to be 30–60 nm. The EDX spectra showed the purity of the material and the complete chemical composition of the synthesized AgNPs. The parasitic inhibition was dose-dependent. The synthesized AgNPs showed considerable antiplasmodial activity than the crude methanol and aqueous leaf extract of E.hirta. The maximum efficacy was

Abstract: Green synthesis of silver nanoparticles using banana sap as a solvent, reducing agent and capping agent is reported in this work. Banana sap has also been used as a binder to incorporate silver nanoparticles into cotton fabric. UV-Visible spectroscopy was used to monitor the quantitative formation of silver nanoparticles. Silver nanoparticle coated fabric showed high antimicrobial activity against gram negative bacteria such as Pseudomonas aureginosa and Escherichia coli, and gram positive bacteria such as Bacillus subtilis and Staphylococcus aureus.KeywordsGreen synthesis, Silver nanoparticles, banana sap, antimicrobial activity

Abstract: Green chemical approach is adopted for the synthesis of silver nanoparticles (Ag NPs). Since the nanoparticles tend to aggregate during the course of the catalytic reaction, they need to be stabilized by employing a suitable template or a support. Hence the prepared nanoparticles were loaded on titania support and used as a photocatalyst. Silver loaded titania (Ag-TiO₂) is characterized by UV-visible spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS). Prepared composite was also tested for its photocatalytic activity against the degradation of an industrial pollutant Rhodamine B dye. Effect of pH, ratio between the catalyst and the substrate and also the role of free radical generator in the degradation have been tested and summarized in this work.Keywords: Silver nanoparticles, Phytochemical preparation, Green chemical approach, Photocatalysis, Rhodamine B

Abstract: The prospective of the use of the silver nanoparticle complexes of glycyrrhizic acid in combating drug induced oxidative stress was studied by using three different model systems; paracetamol induced acute hepatotoxicity, doxorubicin induced acute cardiotoxicity and cisplatin induced acute renal toxicity in Swiss albino mice. The animals were administered with silver nanoparticle complexes of glycyrrhizic acid prior to the induction of paracetamol/doxorubicin/cisplatin toxicity and various parameters such as serum marker enzymes, tissue antioxidants and hisopathological analyses were performed. The results on the serum marker enzymes, tissue antioxidants and hisopathological analyses established the ability the complexes to offer protection to various organ systems against the oxidative damage induced by the respective drug treatments.Keywords Silver Nanoparticle, histopathology, paracetamol, doxorubicin, cisplatin