Structure of self-assembled n-dodecyl substituted azobenzene poly(phenylene) dendrimers on graphite

The highly ordered structure of a new class of dendrimers, n-dodecyl substituted azobenzene poly( phenylene) dendrimers, which self-assemble on highly oriented pyrolytic graphite surfaces, was studied by atomic force and scanning tunnelling microscopy. The second and third generations of this dendrimer have been investigated for the formation of layers consisting of parallel strips with 4.5 and 5.7 nm spacing, respectively. We found that the lamellar packing of the alkyl chains on the graphite surface was responsible for the macromolecular structure. Annealing above 70 degrees C played an important role in sample preparation. The macromolecular structure was found to be independent of the solvent used during spin-coating.