Structural dependency of pyridine carboxylic acid isomers in metal-organic coordination adsorption for copper corrosion inhibition

We systematically investigate the adsorption behavior and corrosion inhibition efficacy of pyridine carboxylic acid isomers (Picolinic, Nicotinic, Isonicotinic acids) on Cu films in alkaline conditions. By integrating theoretical analyses, density functional theory (DFT) calculations, and experimental techniques, we demonstrate the underlying mechanisms governing the adsorption affinities and corrosion inhibition properties of these isomers. Our results show that Nicotinic acid exhibits the highest adsorption affinity and corrosion inhibition efficiency on Cu films, attributed to its favorable electronic and steric properties that enhance nucleophilic interaction and electron donation capabilities. On the other hand, Picolinic acid hindered by steric effects shows the lowest adsorption affinity and inhibition efficiency. The electrochemical studies confirm that Nicotinic acid significantly lowers the corrosion current density and enhances the polarization resistance, offering superior protection against corrosion. Furthermore, the chemical and electrochemical interactions between the inhibitors and Cu films are detailed, with insights into the modification of the Cu surface's electric structure and the formation of protective layers against oxidation. Our research contributes important insights for the development and use of effective corrosion inhibitors for Cu, especially in semiconductor manufacturing and other industries, highlighting the importance of an isomer's molecular structure in its ability to adsorb and prevent corrosion.