Synthesis, characterization and electrical properties of poly(2,5-, 2,3- and 3,5-dichloroaniline)s Part II. Copolymers with aniline

Poly(2,5-dichloroaniline-co-aniline), poly(2,3-dichloroaniline-co-aniline) and poly(3,5-dichloroaniline-co-aniline) have been synthesized by chemical copolymerization of aniline with the dichloroanilines in aqueous 1 M hydroc hloric acid using potassium dichromate as oxidizing agent. The copolymers w ere synthesized at several molar fractions of dichloroaniline in the feed a nd were characterized by elemental analysis, FT-IR and UV-VIS spectroscopy and by electrochemical method. Moreover, the products were doped with HCl a nd gaseous iodine. The doping level shows strongly variation with compositi on of dichloroaniline in the copolymers. Thus, the conductivity can be cont rolled in a broad range, from 10(-9) to 10(-2) S cm(-1). The relationship b etween composition of copolymer and comonomer feed molar ratio shows that t he dichloroanilines present different reactivity in the copolymerization wi th aniline. Conductivities and UV-VIS spectra of products are compared with those of polyaniline and they are shown to be consistent with a diminution in pi -conjugation of copolymers caused by the dihalogenation. (C) 2001 El sevier Science B.V. All rights reserved.