Permeability of mixed self-assembled monolayers of poly(3-dodecylthiophene) and 3-mercaptopropionic acid on gold electrodes

Abstract

Mixed self-assembled monolayers of poly(3-dodecyl-thiophene)(PDT) and 3-mercaptopropionic acid (MPA) have been studied for controlling the permeability of monolayers towards ionic species in solution. During the formation of the monolayer anionic MPA molecules were incorporated in the framework of PDT where defects existed. Differences in permeability were observed in a solution of Fe(CN)₆^3––Ru(NH₃)₆³⁺ mixture by varying the corresponding molecules used for filling the defects. The exclusion of anionic species at the PDT–MPA monolayer offered substantial improvement in the selectivity of voltammetric determination of dopamine against ascorbic acid.