PERMEABILITY OF N-ALKANETHIOLATE MONOLAYERS ADSORBED ON COPPER SURFACES TO COBALTOCENIUM ION FROM ACETONITRILE SOLUTIONS

Rotating-disk voltammetry of cobaltocenium hexafluorophosphate at copper electrodes coated with monolayers of n-alkanethiols (CnH2n+1 SH where n=6, 9, 12, 14 and 18) in 0.1M LiClO4-MeCN indicates that the diffusion of the solute within the monolayer film is explained not by the pinhole model but by the permeation model. The permeability of the monolayers to cobaltocenium ion is nearly constant (2 X 10(-8) cm2s-1) when the number of carbons in alkanethiol is more than 12.