Polymorphism in Self-Assembled Structures of 9-Anthracene Carboxylic Acid on Ag(111)

Abstract

Surface self-assembly process of 9-anthracene carboxylic acid (AnCA) on Ag(111) was investigated using STM. Depending on the molecular surface density, four spontaneously formed and one annealed AnCA ordered phases were observed, namely a straight belt phase, a zigzag double-belt phase, two simpler dimer phases, and a kagome phase. The two high-density belt phases possess large unit cells on the scale length of 10 nm, which are seldom observed in molecular self-assembled structures. This structural diversity stems from a complicated competition of different interactions of AnCA molecules on metal surface, including intermolecular and molecular-substrate interactions, as well as the steric demand from high molecular surface density.

Thermodynamics of Rigid Self-Assembled Crystals: Molecular Simulation of Two-Phase Systems under External Fields

“…Methods for obtaining solid surfaces with atomic-level smoothness over a large area are also well known. An inherent problem in the production of ultrathin functional organic films is concentration and temperature polymorphism. − An observed structure of the self-assembling monolayers (SAMs) results from a delicate balance between intermolecular and molecule–surface interactions. A complicating circumstance is that the adsorption of functional organic molecules usually leads to a decrease in the entropy of the system. ,,,, It results in an increased susceptibility of the system free energy even to weak intermolecular interactions.…”

Coexisting Chiral Two-Dimensional Self-Assembled Structures of 1,2,3,4-Tetrahydronaphthalene Molecules: Porous Pinwheel Nanoarchitecture and Close-Packed Herringbone Arrangement

“…This is of great technological interest as chiral nanoarchitectures have promising potentials for applications in nanotechnology . Chiral nanoarchitectures can emerge from molecular self-assembly. , 2D chirality can result from the self-assembly of chiral building blocks , and prochiral building blocks. − In that case, the chirality of the molecule is transferred to the molecular assembly . Chiral structure can also be achieved using achiral molecules. ,,,, In that case, the chirality results from the specific arrangement of the molecules.…”

Two-Dimensional Chiral Self-Assembly of Barbituric-Acid-Functionalized Naphthelene Derivatives

“…As molecules on surfaces may adopt different two-dimensional (2D) packing, assessing molecular arrangement at the atomic scale is essential. Chiral nanoarchitectures have been engineered to take advantage of molecular self-assembly. − Two-dimensional chirality has been observed to result from the self-assembly of chiral , and prochiral building blocks − on flat surfaces. Chiral arrangements have also been created using achiral molecules. ,,,, The chirality of the organic layer then results from the specific arrangement of the molecules.…”