Self-assembly of alkanoic acids on gold surfaces modified by underpotential deposition

We present an alternative to self-assembled monolayers (SAMs) of ω-functionalized alkanethiols on gold. Substrates utilized here are gold modified by electrochemical deposition of silver or copper monolayers. The metal adlayers promote anchoring of carboxylate headgroups and assembly of ω-alkanoic acids, which would otherwise exhibit no chemisorption on bare gold. Infrared reflectance absorption spectroscopy shows that the films exhibit general characteristics of SAMs. The binding scheme is different from SAMs of alkanethiols on gold and alkanoic acids on silver or copper surfaces. Wetability results obtained from contact angle measurements indicate that such films are more reproducible than SAMs of alkanoic acids on bulk silver and copper.