April 6, 2005:

Our group is exploring conjugated polymers (CPs) for corrosion control of aluminum alloys, motivated by the desire to find suitable replacements for the chromate-based coatings currently used for corrosion control of these alloys. Several unique properties of CPs distinguish them from traditional organic coatings used for corrosion control of metals. The doped (partially oxidized) form of the polymer is electronically conductive and also redox active, so interesting and potentially beneficial interactions of the polymer with the metal substrate are anticipated. One factor that limits the application of CPs as corrosion control coatings is the difficulty in casting such polymers as films or coatings. Since most common conjugated polymers (e.g., polypyrrole or polythiophene) are insoluble in environmentally friendly solvents such as water or alcohol, processibility is a key issue.

This seminar will begin with a general introduction to the synthesis, properties and applications of conjugated polymers. The important issues surrounding the application of conjugated polymers as corrosion control coatings will be presented. Then we will describe an approach using electron transfer mediation for the direct electrodeposition of polypyrrole films onto Al and Al alloy (Al 2024-T3). The influence of such films on the corrosion behavior of the alloy is being investigated by various scanning probe techniques, including the scanning vibrating electrode, scanning pH and oxygen microelectrodes and scanning electrochemical microscopy. Selected results and conclusions from these studies will be presented.