Effect of polymerization conditions on the properties of polypyrrole prepared in the presence of sodium bis(2-ethylhexyl) sulfosuccinate

Abstract

Polypyrrole (PPy) was synthesized by chemical oxidative polymerization of pyrrole in aqueous solution containing an oxidant, ferric sulfate, ferric chloride or potassium peroxydisulfate. An anionic surfactant, sodium bis(2-ethylhexyl) sulfosuccinate (AOT), was used as an additive. The elemental analysis and FTIR spectroscopy proved that a part of the anionic surfactant was incorporated into PPy similarly like the doping anion. This results in a more compact morphology and reduced sizes of the PPy globules. Furthermore, the addition of AOT to the reaction mixture results in significantly increased conductivity, especially when ferric sulfate was used for pyrrole polymerization. PPy synthesized in polymerization solution containing ferric sulfate and at molar ratio [pyrrole]/[AOT]=7 reached conductivity as high as 15 S cm −1, while the same experiment performed in the absence of AOT yielded a product with conductivity of 0.032 S cm −1 only. The conductivity measurement during cyclic thermal treatment of samples showed a stabilizing effect of AOT on conductivity of PPy compared with PPy samples prepared without AOT.