Synthesis and characterization of polyanilines doped with several carboxylic acids and with a carboxylic acid equivalent

Polyanilines (PANIs) doped with several organic acids-maleic acid, squaric acid and 2-propynoic acid-were chemically synthesized in good yields, while PANI doped with 2,6-dihydroxybenzoic acid did not form under similar polymerization conditions. The resulting PANIs were characterized by spectroscopic and thermal analysis, and it was found that the spectroscopic and thermal properties of these PANIs were affected by the type of dopant ion. Formation of different oxidation states of these PANIs were confirmed by the spectroscopic (UV-visible and FT-IR) analysis. Thermogravimetric analysis suggested that PANI doped with maleic acid indicated higher thermal stability than those with the other dopants. The yield and conductivity of PANI doped with maleic acid were found to be higher than those with the other dopants. The PANI doped with 2-propynoic acid was readily soluble in organic solvents including tetrahydrofuran and dioxane. (c) 2005 Society of Chemical Industry.