X‐Ray Photoelectron Spectroscopic Studies of Metal/Inhibitor Systems: Structure and Bonding at the Iron/Amine Interface

Ethylenediamine, triethylenetetramine, 1,4‐bis(3‐aminopropyl)piperazine, and poly(ethylenimine) were individually chemisorbed onto an iron substrate. Chemisorption proceeded without new bands appearing in either the iron or oxygen photoelectron spectra, without the surface iron atoms being oxidized, and without either oxide or hydroxide anions being displaced from the passive film. When ethylenediamine was adsorbed only one N(1s) photoelectron band was observed (399.9 eV), while the other amines exhibited two N(1s) photoelectron bands (399.9 and 401.7 eV). The existence of these two amine bands is interpreted in terms of possible amine adsorption mechanisms and in terms of structural constraints inherent within the molecule or arising during the adsorption process or both.