title: Self-assembly of trimesic acid at the liquid-solid interface-a study of solvent-induced polymorphism.
abstract: A scanning tunneling microscope operated under ambient conditions was utilized to study the self-assembly of trimesic acid (TMA) at the liquid-solid interface. On a graphite substrate, two different open, loosely packed, two-dimensional hydrogen-bond networks were found. Both structures exhibit a periodic arrangement of approximately 1.0 nm wide cavities, which can be used for the co-adsorption of another species (guest) within the cells of this host system. These two polymorphs ("chickenwire" and "flower" structures) differ in their molecular packing density and hydrogen-bonding schemes. Using a homologous series of alkanoic acids as solvents, ranging from butyric to nonanoic, selective self-assembly of either the "flower" or "chickenwire" forms was achieved on a graphite surface. Solubility of TMA in these acid solvents was found to decrease with increasing chain length, and the longer-chain solvents favored formation of the chickenwire polymorph structure on the surface.
authors.affiliation: Department of Chemistry and Columbia Center for Integrated Science and Engineering, Columbia University, New York, New York 10027, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Lackinger
authors.forename: Stefan
authors.initials: S
authors.lastname: Griessl
authors.forename: Wolfgang M
authors.initials: WM
authors.lastname: Heckl
authors.forename: Michael
authors.initials: M
authors.lastname: Hietschold
authors.forename: George W
authors.initials: GW
authors.lastname: Flynn