File(s) under permanent embargo

Mechanisms governing the enhanced thermal stability of acid and base treated polypyrrole

journal contribution
posted on 01.01.1997, 00:00 authored by K Cheah, Maria ForsythMaria Forsyth, V T Truong, C Olsson-Jacques
One of the major problems associated with the use of polypyrrole (PPy) in a practical engineering application is its poor thermal stability at elevated temperatures, especially in the presence of oxygen and moisture. Several authors have shown that enhanced stability can be achieved through treatment with simple acids and bases. This paper presents a summary of the possible structural changes which occur as a result of these treatments and those that appear to be related to enhanced conductivity stability. A slight increase in conductivity (10–20%) is observed for acid treated PPy films which is found to be the result of protonation of the pyrrole structure. This effect is dramatically enhanced by treatment at high temperatures where an increase in conductivity of >84% can be achieved. Base treatment of the PPy films results in the deprotonation of the pyrrole structure leading to the loss of conductivity (>40%). Preliminary X-ray Photoelectron Spectroscopy (XPS) results indicate that both acid and base treatment resulted in the elimination of reactive sites for oxygen. Long term thermal ageing of these treated films were conducted at 150 °C in air. The conductivity decay behaviour was found to follow multiple first order chemical reaction kinetics.

History

Journal

Synthetic metals

Volume

84

Issue

1-3

Pagination

829 - 830

Publisher

Elsevier S.A.

Location

Basel, Switzerland

ISSN

0379-6779

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1997, Elsevier Science S.A.