XPS study of aged polyaniline films

Abstract

ABSTRACT:In this article, a study of the aging of conducting Polyaniline-Polystyrene blends using X-ray photoelectron spectroscopy (XPS) and UV-visible-near IR analysis is presented. The physicochemical results are compared to those obtained by electrical measurements. XPS results confirm the existence of an oxidation process also deduced by the electrical conductivity studies. The N1s and S2p core level spectra decomposition allows to show that a deprotonation process and cyclization of tertiary amine occur during aging. The absorption spectrum shows a decrease of delocalized charges and the apparition of localized polarons after a long aging time. All these mechanisms are responsible of the electrical conductivity decrease observed during aging at elevated temperature. The results are presented for films of PANI-CSA-PSt blends, but the conclusions can be extended to pure conducting PANI-CSA films.

Polyaniline self‐assembled with DTPA: Facilely tuned morphology and properties

“…Also there is a possibility of sample surface contamination as well as hydrolysis of the polymer chains 34,35 during polymerization leading to this high C/N ratio. The presence of sulfur can be ascribed to ASO 3 2 and HSO 4 2 anions as well as neutral sulfonic acid group ASO 3 H according to the S 2p and O 1s high-resolution XPS (Supporting Information, Figures S4 and S5), [36][37][38] which is in agreement with the FTIR spectra (1040 cm 21 , 696 cm 21 ). 36 These sulfur containing groups may result from decomposition of APS, peroxydisulfate radical attack of the benzene rings, and incomplete hydrolysis of nitrogen or ring-substituted sulfate groups.…”

Polyaniline coated conducting fabrics. Chemical and electrochemical characterization

“…The second peak at 285.7 eV is due to C-N groups of the aniline ring [40]. Finally, the third peak is attributed to C=O or C-O-H groups [41] that appear due to the overoxidation caused during the synthesis by the oxidant (peroxydisulphate), that presents a standard redox potential of 2.123 V [42]. The overoxidation degree can be calculated by the ratio C 287.7 eV / C Total , obtaining a value of 9 % and 10 % for the samples of Pani/HSO 4 -and Pani/Cl -, respectively.…”

Shrinking rate of conducting grains in HCl–protonated polyaniline, polypyrrole, and polypyrrole/polyaniline blends with their thermal aging

“…9,10 Aging appears to be a process in which conducting grains are gradually consumed in a corrosion-like manner, advancing from their outer to central parts. [11][12][13] The electrical conductivity in a material with the granular metal type structure is greatly reduced by the widening of the barrier thickness between the conducting grains. In an easily degrading material the rate of this widening with thermal aging would be expected to be higher than in a more durable one.…”