Organic monolayers chemisorbed on gold observed by scanning probe microscopy

Scanning force (SFM) and scanning tunneling (STM) microscopies are suitable techniques for the investigation of the structure of organic monolayers. Results are presented on thioalkane monolayers and thiolipid monolayers on gold. Both molecules attach covalently to the gold surface. STM images of the self assembled dodecanethiol layer display the molecular order of the film and reveal the presence of defects at the molecular scale. Moreover, domains and domain boundaries can be distinguished. Thiolipid layers on gold have been observed by SFM. The monolayer separates in solid-analogous star shaped domains and fluid-analogous domains. Imaging under water demonstrates the stability of the layer.