Surface potential studies of alkyl-thiol monolayers adsorbed on gold

The surface potential (contact potential difference) of monolayers of alkyl thiols adsorbed on gold have been measured using the Kelvin technique. The potential has been found to vary linearly with increasing chain length, n, for 6n22. The variation is discussed in terms of the changing nature of the permittivity of the hydrocarbon portion of the monolayer, a factor often ignored in studies self-assembled monolayers.