Surface initiated polymerization of thiophene and pyrrole monomers on poly(terthiophene) films and oligothiophene monolayers

Thin polyterthiophene films and oligothiophene-based self-assembled monolayers (SAMs) on indium tin oxide (ITO) and gold electrodes have been coupled with different pyrrole- and thiophene-based monomers(heterocoupling). Since the corresponding homopolymers are soluble in the electrochemical medium, only the surface-coupled polymer remains on the electrode and is detected. The method when applied to monolayers allows the formation of nanometer-size layers of polyconjugated polymers with nominally normal orientation of the chain to the surface. Thin films and SAMs were characterized before and after coupling by cyclic voltammetry, UV-vis and IR reflection absorption spectroscopy, and X-ray photoelectron spectroscopy. Microcontact printing on gold and ITO surfaces resulted in patterns for which atomic force microscopy evidenced strong height enhancement after heterocoupling.