Self-Assembly of Aromatic Carboxylic Acids at the Liquid-Solid Interface

Self-assembled monolayers (SAMs) are widely employed systems in nanoscience as the flexibility in their design through variation of different parts of the molecules comprising tail group, spacer, and head group enables the tailoring of physical and chemical properties of surfaces and interfaces.
The structure of SAMs is determined by a balance of different factors involving intermolecular and molecule-substrate interactions Molecular geometry is another factor which seems an obvious one but, somewhat surprising, has been explored very little. Whereas simple geometries yield dense layers, more complex shapes provide access to open structures which offers new opportunities for the control of dimensions, properties and assembly of patterns at the ultrasmall length scale.
Contrasting thiols (-SH) or silanes (e.g. -SiCl3) which are mostly used for SAMs and, thus, have been extensively studied, SAMs of aromatic carboxylic acids have been investigated in more detail only rather recently. Constituting an essential element of metal-organic frameworks (MOFs) they exhibit a large structural variety, yet to be explored for the design of SAMs.
The objective of the project is the self-assembly of aromatic carboxylic acids on metal surfaces. Focusing on molecules with a three-dimensional structure their assembly behavior is studied towards the design of atomically precise templates for controlling chemistry down to the single molecule level. Main techniques employed are scanning probe microscopies (scanning tunneling microscopy (STM) and atomic force microscopy (AFM)) and electron spectroscopies.