Effect of anions on the nucleation and growth mechanism of polyaniline

The effect of anion identity on the viscoelastic properties of polyaniline films during electrochemical film deposition and redox cycling

“…At the upper bound, the round trip for the acoustic wave (to the outer film interface, reflection, and back to the electrode) is 4δ, at which point the intensity of the reflected wave is less than 2% of that for the outgoing wave, so signal quality becomes limiting. (involving progressive or instantaneous nucleation, 2D or 3D growth and the presence of diffusional control, according to the electrolyte); (ii) stability differences (due to differing anion lyophilicity [3,40]) in ion pair formation between the anion and the anilinium species produced during monomer oxidation; or (iii) the Gibbs energy change associated with ion formation in aqueous solution [30], which follows the order SO 4 2-< Cl -< NO 3 -< ClO 4 -for polyaniline salt formation. We do not duplicate these efforts by pursuing the origins of these effects, but rather extend the investigation by exploring their consequences in terms of materials properties.…”

Voltammetric and in situ FT-IRS study of the electropolymerization of o-aminobenzoic acid at gold and graphite carbon electrodes: Influence of pH on the electrochemical behaviour of polymer films

“…53 A major limitation to the industrial exploitation of PANI derives 54 from the fact that, on increasing the pH either during electrosyn-55 thesis or during operation, a significant drop of the electrical 56 conductivity takes place. It was thought that the problem could 57 be solved by the selection of specific counterions [15][16][17][18][19]. The role as an interesting option to achieve this purpose [20][21][22].…”

Microspheres of Conducting Poly(N-methylaniline)

“…[25][26][27] The film formation process and the resulting film structure of PANI are known to be affected by anions and the different types of mechanisms have been discussed in terms of potential-step chronoamperograms. 28 We have observed the difference in chronoamperogram during electropolymerization of PNMAs between the two anion groups, i.e., BF 4 À and ClO 4 À , and Cl À , NO 3 À and SO 4 2À . 29 After the initial current maximum, PNMA films prepared in solutions containing either of anions of the latter group showed an increase in current with time, indicating a marked enhancement of an effective surface area due to a polymer growth accompanying a nucleation on the substrate.…”