Study of electron transfer kinetics on SAM of alkanethiol formed in non-aqueous solvents

Abstract

We find from literature that relatively less attention has been paid to the study of blocking properties of alkanethiol SAMs in non-aqueous solvents primarily due to their perceived instability in these solvents. However we find that this conclusion is due to the insufficient understanding of the electron transfer properties of the monolayer in these solvents. We find that the ferrocene electron transfer through the monolayer is facilitated by the ability of the solvent molecules to interact with the alkanethiol molecule and disorganize the monolayer. We also find that though ethanol has been the most common and preferred solvent for the formation of alkancthiol monolayers on gold, there has not been any detailed electrochemical studies regarding the evaluation of barrier properties of alkanethiol monolayers formed in various other solvents. In this paper we have also evaluated the barrier properties of alkanethiol SAW formed in different non-aqueous solvents using Electrochemical Impedance Spectroscopy. Our impedance results prove that the barrier properties of the SAMs depend to a large extent on the solvent used as adsorption medium.