Doping of polyaniline by corona discharge

In the present article it is shown that a corona discharge can be employed to dope thin films of polyaniline (PANI) coated on poly(ethylene terephthal ate) films, allowing the electrical conductivity to be tuned within the ran ge 10(-10) to 0.3 S cm(-1). A study of the effect of different corona condi tions, namely corona treatment for positive and negative polarities, air hu midity, treatment time, corona current, and the geometry of the corona trio de, on the electrical conductivity of the polyaniline is presented. The res ults indicate that the corona discharge leads to protonic doping of polyani line similar to that which occurs in conventional protonic acid solution do ping. Atomic force microscopic analysis shows that, as the PANI is exposed to the corona discharge, its globular morphology is disrupted leading to th e appearance of droplet-like features and a significant decrease in the ave rage height and surface roughness. Doping by corona discharge presents seve ral advantages over the conventional solution method namely that it is a dr y process which does not require use of chemicals reagents, and which is bo th rapid and avoids dopant migration. The latter can be important for appli cations of PANI in microelectronic devices. (C) 2000 American Institute of Physics. [S0021-8979(00)01608-X].