Two-dimensional self-assembly of a two-component molecular system: formation of an ordered and homogeneous molecular mesh.

The formation of nanoscaled objects often relies on the two-dimensional self-assembly of organic molecules on solid substrates, leading to a number of interesting structures with nanometer dimensions. Assembly of single-component systems driven by chain-chain van der Waals interactions, hydrogen bonding, and dipolar interactions governs the structures typically formed. The two-dimensional self-assembly of a two-component molecular system is described here, where the structure involves mixing of the components at the molecular level. A mixture of 5-octadecyloxyisophthalic acid and octanoic acid forms an ordered stoichiometric array of homogeneous nanometer-sized openings of dimension 8.5 A x 13.5 A x1.8 A, verified by atomic resolution scanning tunneling microscopy. Assembly in the structure is driven by van der Waals and hydrogen bonding interactions between the molecular components.