Polyanilines, synthesis electropolymerized

Scheme 1. (Left) Synthesis of Polyaniline by Electropolymerization in the Presence of an Optically Active Acid and (Right) Structure of Oxazoline-Containing Polythiophene 29...

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. 

The combinatorial synthesis based on the combination of microfluidics and electropolymerization was realized with a microchip consisting of two areas microfluidic channels for generation of gradient of two substances and a parallel electrochemical reactor with platinum electrodes (Fig. 13.3). The system was tested for synthesis of polyaniline in the presence of polysulfonic acid. The reagent ratio providing the best efficiency of the polymer synthesis was evaluated. 

The electropolymerization of o-methoxyaniline in the presence of (+)-(lS)- or (-)-(ll )-CSA yields an optically active polyaniline derivative. The polymer shows intense CD bands as a film deposited on an electrode. The polymer is soluble in NMP, CHCI3, DMF, DMSO, and MeOH, and the polymer also showed CD absorption in a solution probably based on a chiral main-chain conformation such as a helix. A film made by spin-coating a mixture of polyaniline with CSA also showed strong CD absorptions, which may be based on a helical conformation of the main chain. The electropolymerization method has been applied to the synthesis of an optically active polypyrrole which may have a helical conformation. ... 

Apart from chemical synthesis, electrochemical synthesis is a versatile method for the preparation of self-doped sulfonated polyaniline in both soluble forms and thin films deposited on an electrode surface. Electropolymerization of sulfonated polyaniline homopolymers and copolymers has been carried out in aqueous and nonaqueous media. Similar to chemical synthesis, electrochemically controlled electrophilic and nucleophilic substitution reactions are also reported. 

The synthesis of ladder polyanilines was attempted through the electropolymerization of o-phenylenediamines or o-aminophenols [699-703]. 

The first successful synthesis of a polyaniline/PPy copolymer was achieved by the (galvanostatic) electropolymerization of mixtures of aniline (0.5 M) and pyrrole (O.l-l.O M) in acetonitrile solvent in the presence of CF3COOH as acid and tetraethylammonium tetrafluoroborate as supporting electrolyte. Differential scanning calorimetry and FTIR measurements confirmed that the electrically conducting product was a mixture of polyaniline, PPy and a random polyaniline/PPy copolymer. ... 

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