The use of fibril materials as substrate for reinforcing polymers has wide industrial applications. In this article, we discuss polyaniline and polypyrrole as conducting polymers to provide electronic conductivity in E-glass fabric reinforced conducting composite with varied degree of composition and conductivity using industrially important polymers polymethylmethacrylate and polyvinyl chloride as a host matrix. Aromatic sulphonic acids such as PXSA, OXSA, PSA, PDSA, RDSA, OCPSA and MCSA were used as a dopant. The influence of the aromatic ring substituents in these dopants over the conductivity and processibility due to various interactions has been studied. The study shows that due to bulk nature of conductivity, shielding effectiveness (SE) increases with increase in conductivity and thickness of a composite. The test samples were characterized by conductivity and electromagnetic shielding effectiveness (EMI SE). The electromagnetic shielding effectiveness was measured by co-axial transmission line method in the frequency range of 0.01–1000MHz. These composites with both side shielded by polypyrrole offered a uniform shielding effectiveness of 69dB.

The growth in the application of electronic devices across a broad spectrum of military, industrial, commercial and consumer sectors has created a new form of pollution known as noise or radio frequency interference (RFI) or electromagnetic radiation or electromagnetic interference (EMI) that can cause interference or malfunctioning of equipment. Therefore, there is a greater need for the effective shielding of components from its adverse effects. This review surveys the shielding materials like metals, conducting plastics and conducting polymers for the control of electromagnetic radiations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Polyniline and polypyrrole were chemically and electrochemically synthesized in presence of pyridine-3-sulphonic acid. These conducting polymers were characterized by FT-IR, UV–vis, XRD, TGA and SEM techniques. Polyaniline showed a conductivity of 4×10−4S/cm while polypyrrole exhibited a conductivity of 6.2×10−2S/cm. The presence of pyridine ring in the dopant enabled the polymers to anchor Pd/or PdO through which the composite can work as catalytic material.

A method is described to obtain gold–polypyrrole nanostructures by reacting gold chloride with pyrrole at toluene–water interphase. By adjusting the concentration of the stabilizer, namely, pyridine-3-sulphonate, the shape of the nanostructures formed at the interphase can be tailored. This novel method facilitates the fabrication of Au–Ppy composite material that gives wider scope for biosensing applications.

Trivalent europium-doped yttrium oxysulfide nanocrystals synthesized using sol–gel thermolysis show significant blue shifts in the excitation bands corresponding to fundamental absorption, charge-transfer absorption. A significant blue shift observed in the fundamental absorption edge for the nanocrystals having an average crystallite size (φ) in the range 9–15nm indicates a strong quantum confinement with a Bohr exciton radius of 5–13nm. Also, the diffuse reflectance spectra and the corresponding Kubelka–Munk plot indicate the possibility of profound decrease in the absorption coefficient of Eu3+–ligand charge-transfer species necessitating further studies in this wide-gap semiconductor nanocrystalline system.

Electrospinning is one of the simplest techniques for obtaining polymer nano fibers. Nanofibers have large surface area to volume ratio and hence have excellent application potential in sensors, filter design etc. Polyaniline (PANI) is the well-known and widely studied conducting polymer, which however, is insoluble in many common organic solvents and hence difficult to process. PANI in its base form is non conductive but it can be made conducting by protonating with an acids such as hydrochloric acid (HCl) or camphor sulphonic acid (CSA). However, it is difficult to electrospin PANI by itself since we need preferably the polymer in solution form. In this study we have formed nanofibers of PANI (CSA) dispersed in Poly Methyl Methacrylate (PMMA) solution in chloroform. The morphology of the electrospun conducting PMMA-PANI composite fibers is studied using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The DC and AC conductivities of these fibers are measured and the results are discussed.

The reversibility of zinc anode in alkaline medium was enhanced by electrostatic deposition of a conducting polymer (polypyrrole). Electropolymerization of pyrrole onto zinc in aqueous medium using an organic acid as dopant is feasible and preferred as zinc is less corrosive in this medium. The structure of the polymer film was analyzed by FT-IR spectroscopy and scanning electron microscopy. The effect of the polypyrrole deposit on the zinc electrode was studied by cyclic voltammetry and charge–discharge cycling.

A procedure to synthesize lower size mono dispersed palladium nanoparticles is described. The nanoparticles are stabilized by lauryl amine and are isolable as dispersible solids. The particles are characterized by UV–Vis, FT-IR, XRD, STM and TEM techniques.

The phenomenon of electrochromism has attracted interest due to its widespread exciting applications, including antidazzle rearview mirrors, high contrast displays superior to liquid crystals and smart windows for energy-saving applications. Most of these applications make use of WO3 films as active electrodes. Recently much effort has been made to understand the electrochromic process occurring in WO3 which is highly dependent on its optical, structural and morphological nature. In this paper the electrochromic behaviour of the electrodeposited WO3 thin film with respect to the various deposition currents is studied. Optical gaps of electrodeposited tungsten trioxide films are studied by focusing attention on the deposition current. The optical band gap, the refractive index and extinction coefficient of the films prepared under various deposition current is also discussed. Film composition and surface morphological studies are also carried out using EDAX and SEM respectively. O-H stretching and W-O stretching is obtained using FT-IR spectrum. The electrodeposition parameters like pH, bath temperature, concentration, deposition time are optimized. The powder X-ray diffraction studies show triclinic structure. The surface compositional analysis was studied by EDAX and the surface morphology was studied by SEM. Optical absorption, transmittance and reflectance spectra were recorded to study the optical band gap and optical constant changes with the deposition current density. The variation of FT-IR spectra with the deposition current densities (0.50, 0.65, 0.75 mA/cm(2) ) are also discussed for the electrodeposited WO3 thin films.

A novel one-pot method to synthesize palladium nanoparticles incorporated polypyrrole films (Pd–Ppy) is described. The films are homogeneous with palladium particles and can be peeled from the electrode surface as a free standing films. Novelty of this procedure is that the palladium particles are prepared and stabilized in presence of the surface-active dopant, dodecylbenzene sulphonic acid sodium salt (NaDBSA), and are incorporated in to the polymer matrix along with dopant during the growth of the film. It is observed that the incorporation of palladium is uniform and homogeneous. An unprecedented catalytic activity by these Pd–Ppy composite layers in enhancing the rate of polymer deposition is observed. The films also electrocatalyze the oxidation of hydrazine more effectively than do the pure Ppy films.

Lightweight grids for lead-acid battery grids have been prepared from acrylonitrile butadiene styrene (ABS) copolymer followed by coating with lead. Subsequently, the grids have been electrochemically coated with a conductive and corrosion-resistant layer of polyaniline. These grids are about 75% lighter than those employed in conventional lead-acid batteries. Commercial-grade 6V/3.5Ah (C 20 -rate) lead-acid batteries have been assembled and characterized employing positive and negative plates constituting these grids. The specific energy of such a lead-acid battery is about 50 Wh/kg. The batteries can withstand fast charge-discharge duty cycles.

Thin GaAs films were prepared by pulse plating from an aqueous solution containing 0.20M GaCl3 and 0.15M As2O3 at a pH of 2 and at room temperature. The current density was kept as 50mAcm−2 the duty cycle was varied in the range 10–50%. The films were deposited on titanium, nickel and tin oxide coated glass substrates. Films exhibited polycrystalline nature with peaks corresponding to single phase GaAs. Optical absorption measurements indicated a direct band gap of 1.40eV. Photoelectrochemical cells were made using the films as photoelectrodes and graphite as counter electrode in 1M polysulphide electrolyte. At 60mWcm−2 illumination, an open circuit voltage of 0.5V and a short circuit current density of 5.0mAcm−2 were observed for the films deposited at a duty cycle of 50%.

Synthesis of silver nanoparticles stabilized by stearic, palmitic and lauric acids is reported. Three reducing agents, which are moderate strong to mild, formaldehyde, triethanolamine and dimethylformamide, are used. The synthesized nanoparticles are dispersible in non-polar solvents such as benzene and toluene. The IR spectra showed the existence of adsorbed fatty acids. The toluene solution of these nanoparticles exhibited a surface plasmon resonance in the range 420–432 nm. It is shown that the silver nanoparticles have an enhanced stability with increasing chain length of the fatty acid. The size of the nanoparticles is greatly influenced by the experimental conditions such as temperature and concentration. The nanoparticles are characterized by UV–vis, FTIR, XRD, AFM and TEM techniques.

GaAs is a III–V compound possessing high mobility and a direct band gap of 1.43 eV, making it a very suitable candidate for photovoltaic applications. Thin GaAs films were prepared by plating an aqueous solution containing GaCl3 and As2O3 at a pH of 2 and at room temperature. The current density was kept at 50 mA cm–2 and the duty cycle was varied in the range 10–50%. The films were deposited on titanium, nickel and tin oxide coated glass substrates. Films exhibited polycrystalline nature with peaks corresponding to single‐phase GaAs. Optical absorption measurements indicated a direct band gap of 1.40 eV. Atomic force microscope measurements indicated uniform coverage with large crystallites for the films deposited at higher duty cycles. Photoelectrochemical cells were made using the films as photoelectrodes and graphite as counter electrode in 1 M polysulphide electrolyte. At 60 mW cm–2 illumination, an open‐circuit voltage of 0.5 V and a short‐circuit current density of 5.0 mA cm–2 were observed for the films deposited at a duty cycle of 50%. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Phosphate doped polyaniline was synthesized from aqueous phosphoric acid containing aniline by chemical oxidation method using ammonium persulphate as oxidant. The polymer was characterized by UV–vis and FT-IR spectroscopic techniques. Using this polymer, a paint with 1% polyaniline was prepared with epoxy binder. The corrosion resistant property of the polymer containing coating on steel was found out by open circuit potential measurements and electrochemical impedance spectroscopic method in 0.1N HCl, 0.1N H3PO4 and 3% NaCl for a duration of 50 days. The coating was able to protect the steel more in 0.1N H3PO4 and 3% NaCl media than in 0.1N HCl.

Aromatic monomers can be polymerised using the chloroaluminate room temperature melt obtained by mixing 1:2 ratio of cetyl pyridinium chloride and anhydrous aluminium chloride miscible in all proportions with organic solvents as an electrolyte. The chloroaluminate (AlCl4−) anion generated in this melt having a tetrahedral symmetry with equal bond lengths and bond angles is the dopant to stabilize macrocation generated near the vicinity of anode to yield better conducting and better ordered electronically conducting free standing polymer film. In this communication, we discuss the polymers derived from benzene and pyrrole and their characterization by various techniques.

A method to enhance the electronic conductivity of polyaniline grafted E-glass fabric is described. The influence of substituted aromatic sulfonic acids as primary dopants on conductivity of the grafted polyaniline-E-glass fabrics is studied. The conducting fabrics obtained in this method were characterized by UV-vis spectroscopy, scanning electron microscopy, X-ray diffraction study, thermogravimetric analysis, and conductivity. Shielding effectiveness measurements on these Pan-E-glass fabrics showed that the performance is improved (i.e., 0.01 MHz = 49 dB, 1000 MHz 7 dB) compared to earlier studies (i.e., 0.05 MHz 37 dB, 1000 MHz 1 dB) without pretreatment of fabrics. Possible application of these fabrics, e.g., for dissipation of electrostatic charge, is suggested. (c) 2005 Wiley Periodicals, Inc.

Conducting polypyrrole is a biological compatible polymer matrix wherein number of drugs and enzymes can be incorporated by way of doping. The polypyrrole, which is obtained as freestanding film by electrochemical polymerization, has gained tremendous recognition as sophisticated electronic measuring device in the field of sensors and drug delivery. In drug delivery the reversing of the potential 100% of the drug can be released and is highly efficient as a biosensor in presence of an enzyme. In this review we discuss the applications of conducting polypyrrole as biosensor for some biomolecules and drug delivery systems.