Electroanalysis, vol.23, no.3, pp.777-783, 2011 (SCI-Expanded)
We report on the electrochemical behaviour and electropolymerization of self-assembled monolayers (SAMs) of methylene blue (MB) on gold electrodes. The SAMs of MB on gold electrodes were prepared by immersing the substrates into a solution of 1.0mM MB in absolute ethanol for different times at room temperature. Cyclic voltammetry experiments exhibited that reductive desorption of MB monolayer takes place at three different potentials on polycrystalline gold electrodes, while reductive desorption of MB monolayer consists of only one peak on single crystal Au(111) substrates. Calculated charge densities for different immersion times indicated that optimal immersion time for self-assembly of MB is 96h. Electropolymerization of SAMs of MB on gold electrode was achieved by applying 0.95V for 1s in 0.1M borate buffer solution (pH: 9.0). It was observed that poly(MB) monolayers are highly stable in acidic media. ATR-FTIR and UV-vis spectra exhibited differences between monomer and polymer monolayers, which are attributed to surface-confined electropolymerization. STM image of poly(MB) monolayer on Au(111) substrate revealed a surface that is covered by well-ordered, collateral nanowires with an average size of 3nm. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.