Camphor sulfonic acid (CSA)–doped poly(o-anisidine) (PoAN) has been
found to possess the electrical conductivity of 10 S/cm. This value is rather low
compared to that of ('200 S/cm) CSA-doped polyaniline, which may arise from a limited
transformation of coil-like conformation to an expanded one. Viscosity data and optical
absorption spectra provided strong evidence for the existence of coil-like CSA-doped
PoAN chains in m-cresol. The shift of IR bands of benzenoid and quinoid rings toward
a lower wave number and the appearance of the bands at '1600 and 1173 cm21 (the IR
is inactive but becomes active on doping) suggested the protonation of CSA-doped
PoAN. The thermogravimetric profile of CSA-doped PoAN showed a five-step decomposition
pattern with the thermal stability up to 134 °C. The mass spectra taken
simultaneously with the thermogram revealed that dopant CSA is completely eliminated
around 360 °C, but the breakdown of polymer chains does not occur very briskly
at this temperature. Composites of CSA-doped PoAN with insulating acrylonitrile–
butadiene–styrene copolymer (ABS) were fabricated, and it was found that the composites
showed a percolation behavior in which the electrical conductivity rose sharply
at about 4 weight % of CSA-doped PoAN in the ABS composite. The STM data
demonstrated the formation of a continuous path at the percolation threshold. The
Poole–Frenkel effect was observed for the conduction scheme in the CSA-doped PoAN/
ABS composite. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4596–4604,
1999