Abstract: | Poly(aniline‐co‐o‐chloroaniline) salts were synthesized by chemical copolymerization of aniline with o‐chloroaniline using three different acids. The polymer salt samples were heat treated at four different temperatures (150, 200, 275 and 375 °C) and the thermal stability of the polymer salts were studied by conductivity, electron paramagnetic resonance (EPR), infrared (IR) and electronic absorption spectral measurements. The conductivity of the copolymers could be controlled in a broad range from 10 S cm−1 for homopolymer of aniline to 10−4 S cm−1 for those of o‐chloroaniline. No structural changes took place up to 200 °C and this was confirmed from EPR, IR and electronic absorption spectra. No definite correlation exists between conductivity and spin concentration. © 2000 Society of Chemical Industry |