AFM and hydrodynamic electrochemical characterization of the self-assembled 1,4-dithiane on gold surface

Polycrystalline gold electrode surface spontaneously modified by 1,4-dithiane (1,4-dt) organosulfur species was characterized by rotating disk electrode (RDE) and electrohydrodynamic impedance (EHD) using Fe(CN)63- as the electrochemical probe molecule. The gold(1 1 1) monocrystal surface was also modified with 1,4-dt to assess the surface morphology by atomic force microscope (AFM). The electrochemical measurements showed that the polycrystalline gold surface modified with 1,4-dt exhibits a typical behavior of a partially blocked surface and that the blocking effect increases with the increase of the immersion time in the precursor solution. The AFM image clearly shows the presence of defects on the modified surface. Even for a high immersion time (72 h) the electrode surface was not entirely blocked. The surface roughness of the Au/1,4-dt is approximately three times greater than the surface roughness of the bare-gold electrode.