The protective nature of dodecanethiol self-assembled monolayers deposited on Au for the electropolymerization of 3-methylthiophene

Self-assembled monolayers (SAMs) of dodecanethiol spontaneously deposited on Au were investigated as electrodes for the electropolymerization of 3-methylthiophene. The bare Au and SAM-Au electrodes were characterized by cyclic voltammetry and spectroscopic ellipsometry in order to study their surface characteristics. The SAMs on Au showed a thickness of 15-20 Angstrom and a densely packed nature that precluded dissolution of An during the polymer growth in non-aqueous acidic solutions. The electrodeposition of poly-3-methylthiophene films on the bare and SAM-Au electrodes was carried out by cyclic voltammetry and chronoamperometry. The presence of the SAM on the electrode surface inhibited the first stages of polymerization of 3-methylthiophene, but after an induction time. compact and uniform films were obtained on the SAM-Au electrodes.