The incorporation of silver nanoparticles into polypyrrole: Conductivity changes (original) (raw)
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Preparation and characterization of hybrid materials based on polypyrrole and silver nanoparticles
Journal of Physics: Conference Series, 2009
Hybrid material is one of the most promising materials classed in the 21 st century because of its unique properties and its advanced applications. In this work, hybrid materials based on polypyrrole (Ppy) and silver nanoparicles were prepared and characterized. The preparation of the hybrid material was performed by the chemical polymerization method. The structure , electrical and thermal properties of Ppy/Ag hybrid materials were characterized by XRD, SEM, and TGA and the conventional four probe method. The results showed that the Ag particles of 4-8 nm were agglomerated during the in-situ polymerization of PPy and formed some clusters with the diameter of 25-150 nm. By the addition of Ag particles, the electrical conductivity of Ppy increased with increasing Ag concentration. The thermal stability of Ppy was significantly improved by modification with Ag particles.
Polypyrrole-silver composites prepared by the reduction of silver ions with polypyrrole nanotubes
Polymer Chemistry, 2013
Polypyrrole nanotubes were prepared by the oxidation of pyrrole with iron(III) chloride in the presence of methyl orange. They were subsequently used for the reduction of silver ions to silver nanoparticles. The nanotubular form of polypyrrole is compared with the classical globular morphology in its ability to reduce silver ions. Both polypyrrole salts and bases were used in the experiments. The content of metallic silver in the resulting composite, determined by thermogravimetric analysis, was 21-31 wt%.
Characterization and electrocatalytic application of silver modified polypyrrole electrodes
Journal of the Serbian Chemical Society, 2005
Silver modified polypyrrole electrodes were prepared with the aim of testing them for the electrooxidation of formaldehyde in alkaline solution. The modification of polypyrrole by immersion in aqueous AgNO 3 solution was studied by cyclic voltammetry and vacuum techniques (AES and XPS). The influence of time of immersion and the thickness of the polypyrrole film, prepared by electrochemical polymerization, on the modification of the polymer were examined. The results acquired from both electrochemical and spectroscopic examinations show that immersion of a polypyrrole electrode in a AgNO 3 solution results in its modification with silver, which is deposited in the elemental state on the surface. The quantity of silver deposited depends not only on the immersion time but also on the thickness of the polymer film. A modified PPy/Ag electrode exhibits catalytic activity for the electrooxidation of CH 2 O in NaOH. In spite of the low quantity of silver, the activity of the electrode for this reaction is comparable to that of a polycrystalline silver electrode.
Polypyrrole-silver Nanocomposite : Synthesis and Characterization
2016
Polypyrrole-Silver (PPy-Ag) nanocomposite has been successfully synthesized by the chemical oxidative polymerization of pyrrole with iron (III) chloride as an oxidant, in the presence of a colloidal suspension of silver nanoparticles. Turkevich method (Citrate reduction method) was used for the synthesis of silver nanoparticles (Ag NPs). The silver nanoparticles were characterized by UV-Visible spectroscopy which showed an absorption band at 423 nm confirming the formation of nanoparticles. PPy-Ag nanocomposite was characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) techniques for morphological and structural confirmations. TEM and SEM images revealed that the silver nanoparticles were well dispersed in the PPy matrix. XRD pattern showed that PPy is amorphous but the presence of the peaks at 2θ values of 38.24°, 44.57°, 64.51° and 78.45° corresponding to a cubic phase ...
2004
Abstract: Silver modified polypyrrole electrodes were prepared with the aim of testing them for the electrooxidation of formaldehyde in alkaline solution. The modification of polypyrrole by immersion in aqueous AgNO3 solution was studied by cyclic voltammetry and vacuum techniques (AES and XPS). The influence of time of immersion and the thickness of the polypyrrole film, prepared by electrochemical polymerization, on the modification of the polymer were examined. The results acquired from both electrochemical and spectroscopic examinations show that immersion of a polypyrrole electrode in a AgNO3 solution results in its modification with silver, which is deposited in the elemental state on the surface. The quantity of silver deposited depends not only on the immersion time but also on the thickness of the polymer film. A modified PPy/Ag electrode exhibits catalytic activity for the electrooxidation of CH2O in NaOH. In spite of the low quantity of silver, the activity of the electro...
Journal of the Chilean Chemical Society, 2006
Electroactive polypyrrole (PPy) films obtained under potentiostatic electropolimerization from aqueous solutions of pyrrole doped with sulfate (SO 4 2-) anions were modified by incorporation of copper (Cu) and silver (Ag) microparticles using electrochemical cementation process. The electrochemically deposited and dissolving processes metals (Cu and Ag) onto and from polypyrrole were investigated. The PPy-Cu and PPy-Ag electrodes were characterized by electrochemical techniques and scanning electron microscopy (SEM) analysis and the electrochemical response of these modified electrodes was compared to that of the unmodified polypyrrole electrode. The results indicate that two forms of metal, valence and elemental ones, can be formed on polypyrrole at a constant cathodic potential. However, only the valence metal can be left on polypyrrole at the anodic potential. The copper and silver particles interact with polypyrrole films involving a strong complex formation affecting its electrochemical behavior. Scanning electron microscopy measurements show that dendritic-like metal aggregates are formed on the film surface. The electrochemical experiments reveal that metal deposition on conducting polymer can be envisaged as an attractive method for the electrodes fabrication.
Composites Science and Technology, 2014
Polypyrrole nanotube-silver nanoparticles nanocomposites (PPy-NTs/Ag-NPs) have been synthesized by in situ chemical reduction of silver nitrate (AgNO 3) by sodium borohydride (NaBH 4) in the presence of pre-synthesized polypyrrole nanotubes (PPy-NTs) by varying the silver concentration. The nanocomposites have been investigated by HRTEM, SEM, XRD, TGA, UV-vis spectroscopy, impedance analyzer and I-V characteristics for their structural, thermal, optical, dielectric and electrical properties. The average diameter of PPy-NTs and silver nanoparticles (Ag-NPs) has been determined to be 130 and 25 nm, respectively. The thermal stability of the nanocomposites is enhanced, which may be attributed to suppression of the degradation of polypyrrole due to dispersion of silver nanoparticles. The enhanced dielectric properties of nanocomposites may be attributed to the interfacial space charge polarization. Significant increase in the ac conductivity of the nanocomposites is attributed to the extra contribution of conductivity from interfacial capacitive regions.
Characterization of Polypyrrole−Silver Nanocomposites Prepared in the Presence of Different Dopants
The Journal of Physical Chemistry B, 2005
Conducting polypyrrole (PPy) powder synthesized by using FeCl 3 × 6 H 2 O and/or Fe(NO 3 ) 3 oxidants was impregnated in silver salt solutions. The stability and decomposition of the material was followed by thermogravimetric measurements. The total silver content was determined by atom absorption spectroscopy (ICP-AAS). The heat and electric conductivities of the composites were measured and correlated with the silver content. The incorporated silver was speciated and measured by X-ray diffraction (XRD). The spectra proved that the chemical state of the silver incorporated into the composite depends on the anion used in the polymerization process. In the case of the polymerization in a nitrate ion containing solution, the impregnation leads exclusively to the formation of metallic silver. The size distribution of the AgCl and Ag nanoparticles, determined from transmission electron microscopy (TEM) pictures in the different composites, proves the formation of a rather uniform species below 10 and 7 nm, respectively. The observations can be correlated with the different interactions in the PPy-chloride/nitrate-silver systems. The redox type interaction based conclusions can be considered as a guide during the preparation of other metal-conducting polymer composites.
Journal of Solid State Electrochemistry, 2018
Silver(I) halide particles embodied in polypyrrole matrices are synthesized and further processed electrochemically to get nanoparticles of silver with significant activity in the surface-enhanced Raman spectroscopy (SERS) of the rhodamine 6G test solute, which is considered as a clear evidence of Ag nanocrystallization. The electrocrystallization of Ag nanoparticles is analyzed using redox charges of composites determined from cyclic voltammograms recorded at various time scales and/or cycle numbers. Pristine PPy/AgX and modified PPy/AgX/AgNP composites are characterized using electrochemical impedance spectroscopy, scanning electron microscopy, and X-ray electron dispersive spectroscopy. The thermodynamic and kinetic conditions of the electrochemical modification of pristine polypyrrole-AgX composites leading to the electrocrystallization of Ag nanoparticles are discussed.
Room Temperature Bulk Synthesis of Silver Nanocables Wrapped with Polypyrrole
Macromolecular Rapid Communications, 2007
Wet chemical synthesis of silver cables wrapped with polypyrrole is reported in aqueous media without use of any surfactant/capping agent and/or template. The method employs direct polymerization of pyrrole in an aqueous solution with AgNO3 as an oxidizing agent. The four probe conductivity results for the as‐synthesized silver nanocables of polypyrrole films were found to be 3, 5, 5, and 9 S · cm−1 for a 1: 2, 1: 1, 1: 0.5, and 1: 0.1 silver‐to‐pyrrole ratio, respectively. This approach can be extended to other monomers such as aniline and N‐methylaniline (NMA) to prepare different morphologies of silver nanostructures. Aniline monomer polymerization occurred at room temperature to produce a coating of a silver mirror on the side walls of the glass vial, as in the case of Tollen's process of making silver mirrors. The silver mirror coating strategy was extended to a poly(ethylene terephthalate) (PET) surface and the resistivity of the polyaniline‐coated Ag nanocomposites were m...