Polyanilines characterization

Somasiri, N.L.D., and A.G. MacDiarmid. 1988. Polyaniline Characterization as a cathode active material in rechargeable batteries in aqueous electrolytes. J Appl Electrochem 18 92. 

M. Angelopoulos, N. Patel, R. Saraf, Amic acid doping of polyaniline-characterization and resulting hlends, Synthetic Metals 1993, 55, 1552. 

A second type of soHd ionic conductors based around polyether compounds such as poly(ethylene oxide) [25322-68-3] (PEO) has been discovered (24) and characterized. These materials foUow equations 23—31 as opposed to the electronically conducting polyacetylene [26571-64-2] and polyaniline type materials. The polyethers can complex and stabilize lithium ions in organic media. They also dissolve salts such as LiClO to produce conducting soHd solutions. The use of these materials in rechargeable lithium batteries has been proposed (25). 

Polyanilines. Initial preparations of polyaniline (PANI) led to insoluble materials that were difficult to characterize. Use of model compounds and polymers (124,125) allowed for definitive stmctural analysis. Poly( phenylene amineimine) (PPAI) was synthesized directiy to demonstrate that PANI is purely para-linked (126). The synthesis was designed so as to allow linkage through the nitrogen atoms only (eq. 9). Comparison of the properties of PPAI and PANI showed PPAI to be an excellent model both stmcturaHy and electronically. 

Besides synthesis, current basic research on conducting polymers is concentrated on structural analysis. Structural parameters — e.g. regularity and homogeneity of chain structures, but also chain length — play an important role in our understanding of the properties of such materials. Research on electropolymerized polymers has concentrated on polypyrrole and polythiophene in particular and, more recently, on polyaniline as well, while of the chemically produced materials polyacetylene stih attracts greatest interest. Spectroscopic methods have proved particularly suitable for characterizing structural properties These comprise surface techniques such as XPS, AES or ATR, on the one hand, and the usual methods of structural analysis, such as NMR, ESR and X-ray diffraction techniques, on the other hand. 

Zengin et al. [41] characterized a polyaniline (PANI)/MWNT composite. The FTIR spectra of the composite film show benzoid and quinoid ring vibrations at 1500cm-1 and 1600 cm-1, respectively, which indicate the presence of emeraldine salt (ES) of polyaniline. A weak broad band near 3400 cm-1 is assigned to the N—H stretching mode. The strong band at 1150cm-1 is characteristic of PANI conductivity. The FTIR spectrum of PANI/MWNT composite in the ES form exhibits several clear differences from the spectrum of neat ES PANI (1) the composite spectrum shows an inverse... 

X. Zhang, J. Zhang, R. Wang, and Z. Liu, Cationic surfactant directed polyaniline/CNT nanocables synthesis, characterization, and enhanced electrical properties. Carbon 42, 1455—1461 (2004). 

Intercalation of polyaniline between MoS2 layers produced nanoscale molecular composites with unusual charge transport properties [119]. Recent advances in the preparation, characterization, and utilization of conducting polymers intercalated into layered solids were surveyed [120],... 

AlvaK, Kumar J, Marx KA et al (1997) Enzymatic synthesis and characterization of a novel water soluble polyaniline poly(2, 5 diamino benzene sulfonic acid). Macromolecules 30 4024-4029... 

The formation of -aminodiphenylamine is supposed to be the key intermediate in the formation of a dark green precipitate at the electrode surface during continued electrolysis of acidic aniline solutions. This has been characterized as an oligomer of aniline, for example, as the octamer emeraldine formed by a cascade of head-to-tail condensations [38,39]. Nelson, however, explained it as a mixture of mainly quinhydrone with a small amount of benzidine salt [37]. Today the electropolymerization of aniline under strongly acidic conditions is intensively studied as an important way to form the conducting polymer polyaniline [40] (see Chapters 31 and 32). 

Different electron-conducting polymers (polyaniline, polypyrrole, polythiophene) are considered as convenient substrates for the electrodeposition of highly dispersed metal electrocatalysts. The preparation and the characterization of electronconducting polymers modified by noble metal nanoparticles are first discussed. Then, their catalytic activities are presented for many important electrochemical reactions related to fuel cells oxygen reduction, hydrogen oxidation, oxidation of Cl molecules (formic acid, formaldehyde, methanol, carbon monoxide), and electrooxidation of alcohols and polyols. 

A very unusual and previously unknown oxide of copper, the paramelaconite, CU4O3, was synthesized sonochemically in a polyaniline matrix [136]. An aqueous solution of copper (II) acetate and aniline (1 10 molar ratio) is irradiated by ultrasound to produce nanophased CU4O3 embedded in a polyaniline matrix. The as-prepared Cu403-polyaniline is characterized by X-ray diffraction (XRD), and other methods. The mechanism for the fabrication of Cu403-polyaniline is proposed and discussed. This method is general and works also for the production of nanocrystalline Fe304 and CU2O embedded in polyaniline. This technique is also an easy route for the production of other metal oxides embedded in polyaniline. 

Athawale, A. A., Bhagwat, S. V. Synthesis and characterization of novel copper/polyaniline nanocomposite and application as a catalyst in the Wacker oxidation reaction. J. Appl. Polym. Sci. 2003, 89, 2412-2417. 

Polydimethylsiloxane and Zr oxo species have been reacted to give hybrid materials which were characterized by solid-state NMR.149 TEOS/PEG (polyethylene glycol) materials are biphasic systems. The materials were studied by 13C NMR, EPR, and thermal analysis.150 Other systems studied include titania/polyvinylacetate,151 titania/PEG,152 silica/polyacrylates,153 polyimide/ silica,154"156 linseed oil alkyds/titania,157 and PVC/titania and vanadia/sulfonated polyaniline... 

Inelastic neutron scattering studies have shown [7-11] that many hydrogen-bonded crystals [potassium carbonate (i.e., KHCO3), various polyanilines, Ca(OH)2, and others] are characterized by the proton dynamics that is very decoupled from the backbone lattice. 

Ghosh et al. characterized polyaniline/IL composites with the help of NMR [72] and found no reactivity between the two components. Similar findings have been reported by Pringle et al. [73], who synthesized polypyrrole in an phosphonium-based IL. 31P, 19F, and 13C solid state NMR revealed incorporation of the IL during film growth which could easily be eliminated from the polymer via oxidation. 

Zhou, Y. Freitag, M. Hone, J. Staii, C. Johnson, A. T. Pinto, N. J. MacDiarmid, A. G., Fabrication and electrical characterization of polyaniline-based nanofibers with diameter below 30nm, Appl. Phys. Lett. 2003, 83, 3800-3802... 

The system was further characterized by in situ electrochemical/surface plasmon resonance (SPR) measurements, " and surface plasmon resonance spectroscopy was introduced as a means to follow bioelectrocatalytic transformations. Surface plasmon resonance spectroscopy (SPR) is a useful method for the characterization of the refractive index and thickness of interfaces associated with Au surfaces (or Ag surfaces). " In fact, SPR spectroscopy is a common practice in biosensing, and numerous examples that follow the formation of biorecognition complexes on SPR active surfaces have been reported.The redox transformations of polyaniline... 

Leon Kane-Maguire, Ph.D., is currently a project leader in the ARC Centre of Excellence for Electromaterials Science at the University of Wollongong. His research interests are the synthesis of conducting organic polymers and characterizing their stereochemical and photophysical properties. A strong focus of his recent work has been the synthesis of chiral conducting polymers (especially polyanilines) and their use as novel chiral electrodes for electrochemical asymmetric synthesis. 

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