Molecular self-assembled monolayers are films made up of long chain organic molecules, essentially alkanes, which spontaneously form on certain solid substrates by immersing the substrate in a solution of an active surfactant in an organic solvent. The organic monolayers formed through self-assembly are usually closely packed and, therefore, have a highly ordered structure .
The self-assembled monolayer in question in this module consists of sulfur-terminated n-alkanes, namely, , where n = 15. The head group, viz., SH, is chemisorbed onto a gilded solid surface, the alkane chain consists of methylene, , groups, while the free surface (tail group) consists of a methyl group, .
The simplest (n = 15)/gold(111) SAM consists of a commensurate overlayer structure with one alkanethiol chain in the two-dimensional unit cell, according to electron diffraction results .
large circles: gold atoms; small circles: locations of SH groups
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