Cyclic voltammetry studies of octadecanethiol self-assembled monolayers in different concentrations of Fe(CN)₆^3-/ Fe(CN)₆^4-

Octadecanethiol self-assembled monolayers derivatized gold electrode in different concentrations of Fe(CN)₆^3-/4- was studied by cyclic voltammetry. The cyclic voltammetric responses display a series of inverse sigmoidal curves for the SAMs in the solution of various concentration of Fe(CN)₆^3-/4-. A new concept of apparent effective thickness of self-assembled monolayers is established on the base of the measurements of cyclic voltammetry. It is determined that the apparent effective thickness of the SAMs is lower than the length of chain of octadecanethiol. Defect sites may be present in the alkanethiol monolayers. The apparent effective thickness can be used to describe the quality of SAMs quantitatively.