Stability of polyaniline in air and acidic water

Abstract

Polyaniline is a member of the class of electrically conducting polymers, having possible commercial applications such as coatings. Aqueous-based polyaniline coatings are preferred over organic solvent or concentrated strong acid based coatings because water is not a pollutant. The overall goal of this study was to further the development of water-based polyaniline coatings by an examination of the effect of acidic water (pH 1.18) and air on polyaniline. Knowledge of the effect of water on the structure, molecular weight, electrical conductivity, and diffusion of the dopant assisted in ascertaining whether polyaniline degraded with water exposure. Knowledge of how Fourier transform infrared (FTIR) spectra would be affected by dry air was important for determining if polyaniline was chemically stable with time. The results showed that the molecular weight, ultraviolet-visible and FTIR spectra, and carbon-to-nitrogen molar ratio in the polymer backbone all remained unchanged during acidic water immersion. The constant nature of these physical parameters showed a high degree of water stability. A chloride ion diffusion coefficient of 2.8 to 85 ϫ 10 Ϫ9 cm 2 /h, the chloride concentration, and the electrical conductivity were also measured with the water immersion time. Aging polyaniline powders in a desiccator for 5 years showed no effect on the molecular structure, as indicated by the FTIR spectrum.

Potassium Ion Selective Electrode Using Polyaniline and Matrix-Supported Ion-Selective PVC Membrane

“…Many electronically conducting polymers including polypyrroles [24], poly(3-octylthiophene) (POT) [25], and poly(3,4-etyhlene-dioxythiophene) (PEDOT) [26], and polyaniline (PANI) [27] were tested as ion-to-electron transducers. It should be noted that PANI does not prevent water layer formation; rather, its conductivity is stable over a wide range of water content [28], [29]. Therefore, in this study, PANI was chosen due to its high conductivity in presence of water (10 −3 − 10 −2 S/cm) and facile synthesis.…”

Synthesis and characteristics of a semi‐interpenetrating polymer network based on chitosan/polyaniline under different pH conditions

“…PANi has four different forms, in which its repeating units contain two different entities at different relative weights: fully reduced leucoemeraldine base, half‐oxidized EB, fully oxidized pernigraniline base,17 and doped in a protonic acid that is designated ES 18. Among other forms of PANi, EB is of particular interest because it can be rendered conductive by protonation with a sufficiently strong protonic acid such as hydrochloric acid (HCl) 19, 20.…”

Spiral stir bar sorptive extraction with polyaniline‐polydimethylsiloxane sol‐gel packings for the analysis of trace estrogens in environmental water and animal‐derived food samples

“…PANi particles were synthesized by chemical oxidation polymerization [27], and the details are included in Supporting Information. PANi structures are shown in Supporting Information Figure S1.…”