Preparation and properties of polyaniline doped with poly(thiophenylenesulfonic acid)

A novel polyaromatic acid, poly(thiophenylenesulfonic acid) (PTPSA), prepared from a soluble precursor of poly(arylenesulfonium salt) was employed as a dopant for polyaniline (PAn). The electro-oxidative polymerization of aniline in PTPSA aqueous solution gives an electroactive PAn/PTPSA composite with three redox couples at 0.16, 0.53, and 0.71V (vs. SCE). Composites of different molar ratio ([SO₃H]/[An] = 0.10, 0.21, 0.42, 0.50, 0.83, 1.67) was prepared in order to confirm the transformation from the emeraldine base to its PTPSA salt, where a quantitative doping reaction was observed by means of UV-VIS and IR measurements. The thermogravimetric analysis revealed that the composites do not decompose up to 200°C in nitrogen atmosphere. The composite ([SO₃H]/[An] = 0.50) shows an electrical conductivity of 1.5 S · cm^-1 at 30°C and 3.0 × 10^-1 S · cm^-1 at 170°C. The composite retains its conductivity after heating at 150°C for 24 h.