The influence of chain length and ripening time on the self-assembly of alkylamines on mica

The influence of chain length and ripening time on the self-assembly of tetradecyl (C(14)), hexadecyl (C(16)), and octadecylamine (C(16)) on mica has been studied by atomic force microscopy. The overall process can be described in three stages characterized by different time scales. First, alkylamine molecules adsorb in a process controlled by water mediated interactions of the NH(2) head groups and mica. Second, surface diffusion and aggregation into islands takes place, driven by energy interactions between alkyl chains. The third stage consists of a progressive tilt of the self-assembled molecules towards the surface, driven by relaxation of the electrostatic repulsion between protonated amino groups due to water uptake from atmosphere.