Structure investigations of electrical conducting plasmapolymerized films from 2-iodothiophene

In recent years, there has been increasing interest in plasma polymerized films because of their outstanding chemical, mechanical, thermal and electrical properties. They are quite different from conventional polymeric films. Though plasma polymerized films are normally non-conducting, except metal containing films, some intrinsically conducting films have been developed. Doping, usually with iodine, strongly enhances the conductivity of these films. Unfortunately, a direct doping with elemental iodine during the plasma deposition is difficult to perform, hence a new deposition route was investigated using the iodine containing monomer 2-iodothiophene. Films with high electrical conductivity (10high-1 - 10high-6 S cmhigh-1) were prepared and their chemical structure was investigated by XPS and FTIR. Especially the state of charge of the doping element iodine (e.g., Isub3-, Isub5-) may be important for the conduction mechanism.