Vapor phase polymerization of pyrrole and thiophene using iron(III) sulfonates as oxidizing agents

Vapor phase polymerization is a versatile technique that can be used to obtain highly conducting coatings of conjugated polymer on both conducting and nonconducting substrates. This is demonstrated here by preparation of polypyrrole, polybithiopene, and polyterthiopene, coatings that otherwise must be prepared electrochemically in order to achieve the desired high conjugation. The method is based on the use of organic ferric sulfonates as oxidant as these salts easily form smooth, noncrystalline films. By proper choice of the sulfonate anion, the oxidizing power of the ferric salt can be varied over a wide range. The described technique can easily be adapted to different patterning techniques.