Preparation and characterization of self-assembled monolayers of octadecylamine on mica using hydrophobic solvents

The formation of self-assembled monolayers of octadecylamine on mica from chloroform solutions has been studied ex situ with atomic force microscopy (AFM). Growth occurs in the form of islands with structure and properties that depend critically on preparation conditions. Inside the islands, the molecules are oriented such that they expose the terminal CH3 group and are tilted with respect to the normal direction of the surface. The weak bond between mica and the polar amino (-NH2) group results in weak mechanical stability of the islands, which are easily damaged by the AFM tip during repetitive scans. The influence of several preparation parameters on the islands' structure has been analyzed and discussed on the basis of a model involving residual water molecules on the mica substrate.