THE STRUCTURE OF 5-MEMBERED POLY-HETEROCYCLES

Thin films of Poly-N-Methylpyrrole (PNMePy), Poly-3-Methylthiophene (P3MeTh), and Poly-Bithiophene (PBiTh) are electrochemically formed on gold- and palladium-electrodes. During oxidation, which switches the conductivity of the polymer from an insulating state to metallic conduction, anions are intercalated in the polymer to neutralize the positive charge on the polymer backbone. The electrochemical quartz micro balance allows comparison of the coulometric data with the mass of anions intercalated during this process. A small amount of solvent is additionally incorporated during this process. Mechanical stress within the film causes a visible bending of the electrode. Ionic and electronic resistances are parallel and the lower value determines the reaction site. The polymer films have a high ionic conductivity necessary for hydrogen and oxygen evolution at the substrate surface underneath the polymer film. Electron transfer reactions yield data of the resistance and the pore size of the polymer.