Electropolymerization of benzene and biphenyl in organic media: Influence of different parameters (solvent,water, acidity,salt) on the formation of polyparaphenylene films (PPP)

The electrosynthesis of polyparaphenylene films (PPP) by oxidation of benzene or biphenyl on a Pt electrode was studied in different organic media. Film formation was possible only if the solvent had acidic properties according to the Lewis concept, and if the water content of this medium was less than 5 × 10^?2M. Addition of an excess of P₂O₅ or CuCl₂ into the medium increased the acidity and improved the adherence and the homogeneity of the films considerably. PPP films were electroactive and conductive if the electrolysis was carried out in the presence of salts containing BF, SbF, PF anions; they were insulating with perchlorate salts. IR analysis of these polymers showed highly crosslinked structures and the chains were constituted of about 10 para coupled phenyl moieties.