Spatially Resolved Surface Analysis of an Octadecanethiol Self-Assembled Monolayer on Mild Steel Using Sum Frequency Generation Imaging Microscopy

Sum frequency generation imaging microscopy has been used to investigate a self-assembled monolayer of an alkanethiol (octadecanethiol, ODT) on a mild steel surface. The images are used to analyze the orientation of the alkanethiol monolayer and the distribution of orientational angles as well as defects in the film. The results show that, on average, ODT forms an ordered monolayer on mild steel when compared to the same monolayer on gold. However, the image analysis suggests that the distribution of tilt angles and conformational defects is greater for ODT on a mild steel surface compared to ODT/Au.