Corrosion studies of organicdithiol/monothiol derived self assembled monolayer on copper substrate towards corrosion protection in 0.5 M NaCl

The corrosion resistance of I-decanthiol (DT), 1,9-nonanedithiol (NDT) and 1,4-benzendimethanethllll lBDMT) sci I' assembled monolayer (SAM) covered copper were investigated using several electrochemical methods Including polarization studies and electrochemical impedance spectroscopy lEIS) in aqueous 0.5 M NaCI solution. The SAM covered surface was characterized by Fourier transform infrared reficetance spectroscopy (FTJR), atomic force microscopy (AFM) and cyclic voltammetry. The inhibition efficiency (IE) of the SAM/copper was investigated by varying: concentration of thiol in solution used for scII' assembly, assembly period for the formation of SAM and effect of solvents (DMF, toluene, ethanol and acetonitrile) for preparing the thiol solution. The inhibition efficiency of the different thiol compounds under similar experimental conditions for copper corrosion was found to be in the following order: NDT > DT > BMDT. The concentration of thiol and self assembly period affect the quality significantly. At the higher concentration, the self asscmbled monolayer was formed immediately after the solution was introduced to a substrate. There was only a marginal elTect of using different solvent for dissolving the thiols on the inhibition efficiency (IE). FTIR and AFM confirm the sciI' assembling of thiols on copper surface