OCTADECYL MERCAPTAN SUB-MONOLAYERS ON SILVER ELECTRODEPOSITED ON GOLDQUARTZ-CRYSTAL MICROBALANCE ELECTRODES

The objective of this work is to accurately and reproducibly control t he amount of alkanethiol self-assembled onto the surface of a gold qua rtz crystal microbalance (QCM) electrode. This reaction is the first s tep in preparing bilayer membranes on gold electrodes that contain cyt ochrome c oxidase. In this work procedures for cleaning the surface of gold QCM electrodes, including use of an oxygen plasma, a UV surface cleaner, and aggressive chemical treatment of the surface, still led t o rates of octadecyl mercaptan (OM) self-assembly that were highly irr eproducible, varying over several orders of magnitude in time. Electro deposition of a silver monolayer onto the surface of gold QCM electrod es affords a surface at which the OM self-assembly reaction can be eas ily controlled. Using the QCM to monitor the self-assembly reaction of OM on the silver-coated gold QCM electrode surface, a selected sub-mo nolayer coverage can be reliably prepared in about 10 min.