Poly(aniline- co-o-aminobenzenesulfonic acid) (PAOABSA) as a water soluble conducting polymerwas synthesized by chemical polymerization. The productivity and the room-temperature conductivity of thecopolymer were measured as a function of the reaction conditions

such as reaction temperature

the ratio ofoxidant to monomer and the degree of sulfonation defined as the ratio of sulfur to nitrogen atoms(S/N). Themain results obtained are summarized as follows : (1) lower reaction temperature (at about 0℃) is favorable for the enhancement of the room-temperature conductivity of the copolymer;(2)higher content of oxidant is unfavorable for increasing the room-temperature conductivity of the copolymer;(3)both productivity and room-temperature conductivity of the copolymer decrease with increase of the degree of sulfonation which was always lower than 0.5 even an excess of ο-aminobenzenesulfonic acid was added

probably because the reactivity ratio of aniline (γ1=2.99±0.05)is much higher than that of ο-aminobenzenesulfonic acid(γ2=0.06±0.02) estimated by using Fineman-Ross method and least square method.