Self-assembled monolayers formed by ammonium pyrrolidine dithiocarbamate on copper surfaces in sodium chloride solution

• Ammonium pyrrolidine dithiocarbamate is an efficient copper inhibitor.
• Its maximum inhibition efficiency in a 3% NaCl solution can reach over 98%.
• The two sulfur atoms of the inhibitor are the most active adsorption sites.

The inhibiting effect of ammonium pyrrolidine dithiocarbamate (APDTC) self-assembled monolayers (SAMs) on the corrosion of copper surface in a 3 wt.% NaCl solution is reported using electrochemical methods, surface analysis and theoretical studies. The optimum conditions for formation of SAMs established using impedance studies are 1 mmol L−1 concentration of APDTC and an immersion period of 8 h and its maximum inhibition efficiency could reach 98.7%. Infrared spectrum and energy dispersive spectroscopy analyses all show that APDTC is adsorbed on the copper surface and quantum chemical calculation results reveal that the sulfur atoms are the most active adsorption sites.