关键词: 自组装单分子层膜, 修饰电极, 膜电阻, 电阻极化

Abstract: The electrochemical behavior of gold electrode modified by hexadecanethiol self_assembled monolayer (SAM) in the solution of Fe(CN) 6 3- /Fe(CN) 6 4- was investigated by cyclic voltammetry and ac impedance spectroscopy. The pinhole_free SAM_modified gold electrode has excellent blocking properties to the interfacial electron transfer from redox couple in solution to the substrate. The current increased exponentially with the overpotential at the high potential region. A good linear relationship between ln( I/η ) and η 1/2 was observed. A model system Au/SAM/Hg was constructed and its I～V curve was measured. Similar phenomena were observed. There was also a linear relationship between ln( I/V ) and V 1/2 at high voltage region. It is proposed that the characteristic of pinhole_free SAM_modified gold electrode in solution of Fe(CN) 6 3- /Fe(CN) 6 4- mainly belongs to the resistance of the self_assembled monolayer itself.