Studies on Polythiophene Films Prepared by Electropolymerization

The electrochemical polymerization of thiophene to BF4- doped polythiophene using electrochemical cell fitted with a platinum working electrode and ammonium fluoroborate in propylene carbonate electrolyte showed the efficiency of electropolymerization reaching to 100%. The aqueous ammonia is very commonly used as undoping agent for conducting polymers. The work on the undoping of BF4- doped polythiophene by dry ammonia was carried out in order to corroborate the mechanism of undoping vis a vis polyacetylene. The work on the mechanism of the dry ammonia undoping of BF4 - doped polythiophene (PThn+:nBF4?) by dry ammonia is novel in the sense the mechanism is strongly supported by our previous works and the scanning electron micrographs showing the formation of NH4F crystals. The mechanism of irreversible undoping of BF4 - doped polythiophene by moisture is also proposed. The scanning electron microscopy showed the surface of the BF4 - doped polythiophene films produced to be extremely smooth while the beautiful microdendrites composed of globules were formed on the edges of the working electrode. The microdendritic growths of such morphology have also been observed in polypyrrole produced by electropolymerization.