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Conducting Polyaniline (conducting + polyaniline)
Selected AbstractsSynthesis and characterization of conducting polyaniline-activated carbon nanocompositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Mohammad Rezaul Karim Abstract Conducting polyaniline (PAni)/activated carbon (AC) nanocomposites were synthesized by the in situ chemical polymerization method. The resultant shell,core PAni,AC nanocomposites were characterized by elemental analysis, Fourier transform infrared, scanning electron microscopy, thermal gravimetric analysis, X-ray diffraction, and transmission electron microscopy. We did not observe any significant chemical interaction between the PAni and AC, only core,shell coupling between the AC and the tightly coated polymer chain was revealed. Measurement of the physical properties showed that the incorporation of conducting PAni on to AC particles during chemical synthesis increased electrical conductivity and thermal stability by several orders of magnitude to that of the pristine PAni powders. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1973,1977, 2007 [source] Theoretical study of the oxidative polymerization of aniline with peroxydisulfate: Tetramer formationINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 2 2008-Marjanovi, Gordana Abstract Semi-empirical quantum chemical study of the oxidative polymerization of aniline with ammonium peroxydisulfate, in aqueous solutions without added acid, has been based on the MNDO-PM3 computations of thermodynamic, redox, and acid,base properties of reactive species and the intermediates, combined with the MM2 molecular mechanics force-field method and conductor-like screening model of solvation. The main reaction routes of aniline tetramerization are proposed. The regioselectivity of the formation of aniline tetramers by redox and electrophilic aromatic substitution reactions is analyzed. It was proved that the linear NC4 coupled tetra-aniline is formed as a dominant product by three different pathways: comproportionation redox reaction between N -phenyl-1,4-benzoquinonediimine and 4-aminodiphenylamine, the one-electron oxidation of aniline with its half-oxidized NC4 coupled trimer, and the electrophilic aromatic substitution reaction of aniline with fully oxidized NC4 coupled trianiline nitrenium cation. The electrophilic aromatic substitution reaction of the NC4 coupled aniline trimer with aniline nitrenium cation, as well as the oxidation of aniline with half-oxidized branched trimer, lead to the branched aniline tetramers. The competing character of different tetramerization routes is highlighted. The oxidative intramolecular cyclization of branched oligoanilines and polyaniline, leading to the generation of substituted phenazine units, has been predicted to accompany the classical routes of the polymerization of aniline. Various molecular (branched vs. linear) oligomeric structures produced at different level of acidity during the course of polymerization and their impact on the formation of supramolecular structures of conducting polyaniline (nanorods and nanotubes vs. granular morphology), are discussed. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Constructive modification of conducting polyaniline characteristics in unusual proportion through nanomaterial blend formation with the neutral polymer poly(vinyl pyrrolidone)JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007E. Subramanian Abstract The present work reports an investigation on the modification of conducting polyaniline (PANI) characteristics favorably on blending with the neutral polymer, poly(vinyl pyrrolidone) (PVP) in a systematic variation of their molar ratios (aniline : PVP = 4 : 1, 2 : 1, 1 : 1, 1 : 2, and 1 : 3). Prepared by precipitation technique by conventional in situ chemical oxidative polymerization with ammonium peroxodisulfate in aqueous H2SO4 medium (pH 1.0), these materials have nanometer sizes (, 50,200 nm) and, depending on the molar ratios, exhibit a distinct deviation in physicochemical characteristics from those of pristine PANI prepared in the identical condition. A gradual trend in characteristics is noticed in first three PANI,PVP blends, while an abnormal hike in conductivity, unusual spectral features in IR and UV,vis, hardened nature, and induction of characteristic morphology, crystallinity, and thermal stability are associated with the last two blends that have excess PVP. Thus a division of two sets of nanoblends, one set with less or equal content of PVP and another with excess of PVP, emerges. Evidently, PVP has a tuning effect on PANI through its dopant, supporting matrix and interpenetrating steric stabilizer acts in proportion quite unusual to its neutral nature. The study altogether brings to light a simple way of modification of PANI characteristics by conventional method of blend synthesis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Synthesis and Electrorheological Characterization of Polyaniline/Barium Titanate Hybrid SuspensionMACROMOLECULAR SYMPOSIA, Issue 1 2006Fei Fei Fang Abstract As organic/inorganic composites having attracted much attention due to their heterogeneous physical properties, conducting polyaniline (PANI) and barium titanate (BaTiO3) which possesses large electronic resistance and excellent dielectric strength, were utilized to synthesize PANI/BaTiO3 hybrid which is applicable for an electrorheological (ER) material via ,in-situ' oxidative polymerization. Physical properties of the obtained PANI/BaTiO3 composites were characterized via Fourier-transform infrared spectra (FT-IR), thermogravimetry analysis (TGA), and scanning electron microscopy (SEM). The ER behaviors were investigated via a rotational rheometer, and their shear stresses were fitted using our previously proposed rheological equation of state. [source] pH sensor based on polyaniline and aniline,anthranilic acid copolymer films using quartz crystal microbalance and electronic absorption spectroscopyPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2008M. M. Ayad Abstract The pH sensitivity based on conducting polyaniline (PANI) and copolymer of aniline and o -anthranilic acid (AA) films were studied using quartz crystal microbalance (QCM) technique and UV,Vis spectroscopy. The sensor was constructed from these polymer films coated on the electrode of the QCM. The resonant frequency changes as a function of pH in the range of 2,12 were measured. These changes are quantitative indication of the degree of dedoping or redoping of the polymer films upon the subsequent exposure of the electrode to 0.25,M sulfuric acid and different pH solutions. There are two linear regressions between the frequency change and pH with two different and opposite slopes in the regions from 2 to 9 and 9 to 12. The pH sensitivity of the copolymer film was found to be less than using the PANI film. Thin films of PANI and copolymer, which were chemically polymerized in a sulfuric acid solution, were deposited onto the inner walls of the quartz cuvettes. The UV,Vis absorption spectra of these films were measured in different pH solutions. Relations between the maximum absorption and its wavelength versus pH were constructed. The copolymer film shows some advantages over the PANI film. The difference between the PANI and copolymer films as pH sensors using the QCM and electronic absorption extends from the determination of pKa for both films. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||