Conductivity degradation in oxygen-aged polypyrrole

Abstract

The conductivity of doped polypyrrole, as high as 100 Scm−1 in freshly prepared samples, falls slowly with time on exposure to atmospheric oxygen. Typically, the fall in conductivity is fairly slow at room temperature, but the process can be accelerated by heating samples and measuring the decrease in conductivity as a function of time. Analysis of the kinetics of this process shows a preliminary, 120 min regime in which a surface adsorption-diffusion mechanism with an activation energy of 0.41 eV appears to mediate. Once a degree of adsorbate saturation is attained subsequent behavior is well described by standard bulk diffusion considerations and is activated at 0.48 eV. We propose a mechanism whereby oxygen adsorption onto the surfaces of the polymer fibrils and diffusion into the interior are respective rate limiting steps in the incorporation of oxygen into the closely cross-linked mesh, blocking conducting pathways.

Biostability of electrically conductive polyester fabrics: An in vitro study

“…It is well known that absorption of oxygen onto oxidized PPy leads to the decrease of conductivity, possibly by inhibiting the mobility of the charge carriers. 17,18 Furthermore, the second 1-week incubation apparently had a much greater impact than the first 1-week incubation in reducing the conductivity, meaning the increase of resistivity with incubation was nonlinear and accelerated in the second week. Because the second redoping was again able to greatly bring down the resistivity, it is believed that the increase of resistivity during the second week of incubation was also mainly caused by dedoping.…”

DC conductivity retention of functionalised multiwalled carbon nanotube/polyaniline composites

“…Apart from this, the phenomena also points to the possibility of damage in conjugated PANI chain structure by atmospheric agents. The relationship between aerial oxidation and conductivity deterioration is studied by Tansley et al [33]. They reported that oxygen absorption occurs on the surface of polymers followed by its diffusion into the bulk.…”

“…9b) with S 1 showing more retention than S 2 . There are many changes occurring at high temperature causing deterioration of polymer structure and leading to decrease in conductivity of conducting polymers [25][26][27][28][29][30][31][32][33]. The thermal stability of conductivity of PANI depends upon the nature of dopant and on the morphology of the material.…”

Electrocatalytic Reduction of Oxygen at Anthraquinonedisulfonate/Polypyrrole Composite Film Modified Electrodes and Its Application to the Electrochemical Oxidation of Azo Dye

“…OH and H 2 O 2 generated during the electrolysis on polymer matrix, resulting in the degradation of PPy film [41,42]. On the other hand, it is now known that conducting PPy tends to degrade and lose of part of its electronic conductivity on prolonged exposure to oxygen [43,44]. In addition, the longtime runs in aqueous solution also lead to the conformational relaxation of PPy film [45,46].…”