Synthesis, characterization and electrical properties of poly[bis-(2-aminophenyl)disulfide] and poly[bis-(2-aminophenyl)diselenide] Part II. XPS, ESR, SEM and conductivity study

Poly[bis(2-aminophenyl)disulfide] (DSDA) and poly[bis(2-aminophenyl)diselen ide] (DSeDA) were synthesized by monomer oxidation with ammonium persulphat e at different polymerization times, in 0.5 M H2SO4 and 1 M HCl media. X-ra y photoelectron spectroscopy (XPS) analysis of DSDA shows similar percentag e of imine and amine groups in the polymer, like emeraldine. DSeDA shows di fferent percentages of imine and amine groups, which corresponds to a state different of emeraldine. When the time of polymerization of DSDA is increa sed, a small change in the oxidation state is detected but in DSeDA the num ber of imine groups decreases. When polymerization is carried out in HCl me dia, both polymers present a minimum percentage of chlorine unit with coval ent linkage to macromolecule. Moreover, electron spin resonance (ESR) study shows the presence of nitrogen and carbon radicals in the structure, and b oth radicals should be associated to chlorine or sulfate ions. The two poly mers present low level of conductivity related to low level of doping. The macromolecules present a granular structure, but DSeDA is more pulverulent. (C) 2000 Elsevier Science S.A. All rights reserved.