Properties of chemically prepared polypyrrole with an aqueous solution containing Fe2(SO4)3, a sulfonic surfactant and a phenol derivative

This paper describes chemically prepared polypyrrole (PPy) with an aqueous solution containing Fe2(SO4)3 as an oxidant. PPy having enhanced conductivity and environmental stability was obtained under the coexistence of a sulfonic surfactant and a phenol derivative with an electron-withdrawing group. The effect of the sulfonic surfactant was ascribed to a large-sized sulfonic anion being selectively incorporated into PPy as dopant, because an increase in the yield of PPy depended on the concentration of the surfactant. For PPy synthesized with a solution containing p-nitrophenol (pNPh), a clear increase in the doping ratio was recognized from elemental analysis. Moreover, the conductivity of PPy increased with increasing strength of the electron-withdrawing force of the substituent. The electron-withdrawing substituent of the phenol derivative seems to prevent undesirable side reactions so as to improve the regularity of the PPy backbone.