Alignment of Perfluorinated Supramolecular Columns on the Surfaces of Various Self-Assembled Monolayers

Abstract

We studied the orientation of the hexagonal columnar mesophase formed by self-organization of a perfluorinated supramolecular dendrimer containing a carboxyl (−COOH) headgroup and three perfluorinated (−CF3) tails at surfaces modified with self-assembled monolayers (SAMs). The SAM-modified surfaces studied were composed of an Au(111) substrate modified with one of five types of SAM. The SAM molecules used all had an −SH headgroup, but different terminal groups (−CF3, −CH3, and −OH) and different spacer chain lengths. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and contact angle microscopy results revealed that the lattice parameters and structure of the perfluorinated supramolecular dendrimer are retained, but the orientation of the columns is strongly affected by the characteristics of the SAM surface. The supramolecular columns took on a planar alignment on the −CF3 and −OH terminated SAM surfaces, but exhibited a perpendicular orientation on the −CH3 terminated SAM surface. T...