Doping of chemically synthesized polyaniline

Abstract

Polyaniline was chemically synthesized in aqueous acidic medium (HCl) with ammonium peroxydisulfate [(NH₄)₂S₂O₈] as the oxidizing agent, using a procedure described in the literature. Because the synthesis of polyaniline was carried out in aqueous acidic media, the obtained product consisted of emeraldine hydrochloride. The obtained product was washed several times with water and with HCl solution in which it was synthesized, and then treated with ammonia solution at room temperature overnight to convert it to the base form before doping. CuCl₂, AlCl₃, and ten different organic or protonic acids were examined as dopants in different conditions. We observed that washing of the product, the reaction time and synthesis conditions, the acidity of the reaction media, and the type and concentration of the doping agents all affected the conductivity of polyaniline. The best conductivity (∼ 27 S cm^-1) was obtained by HBr at 0.5 M concentration.

Keywords:

• Polyaniline
• doping
• conductivity
• synthetic metals