Cooperative Rearrangements Leading to Long Range Order in Monolayers of Supramolecular Polymers

Abstract

Using scanning tunneling microscopy (STM), we followed the self-organization process of a supramolecular polymer monolayer deposited on a gold surface. During the growth of ordered domains from small to large scales, the molecule-molecule interactions were found to overrule the coupling to the substrate, causing a reorientation of the monolayer. The flexibility at the molecular level, due to reversible hydrogen bonds, was directly visualized by STM. The supramolecules were able to slide and insert between neighboring molecules, allowing the annihilation of domain boundaries and improving long range order. Large domains were found to cross monoatomic steps on the substrate without perturbation of their order.

A photoelectron diffraction investigation of vanadyl phthalocyanine on Au(111)

“…8) actually appears to show that the 'herring-bone' reconstruction of the Au(111) persists under the VoPc layer, indicating that the molecule has little influence on the Au surface structure and that an incommensurate overlayer structure is most probable. The dominance of intermolecular interactions over the corrugation of the substrate potential in determining the molecular ordering, implied by this incommensuration, has been observed explicitly for at least one other large molecule on this same surface [25].…”

Competition Between Steric Hindrance and Hydrogen Bonding in the Formation of Supramolecular Bottle Brush Polymers

“…[48][49][50] This model predicts in solution the growth of the supramolecular assemblies with increasing concentration and the formation of very long supramolecular polymers at higher concentrations, which was confirmed experimentally by rheology 46,51 , static light scattering [52][53][54] and Scanning Tunneling Microscopy. 55 Preliminary results have recently been obtained both in solution 56 and in the bulk 57 for U2PIB2 ( Figure 1), a bisurea bearing two poly(isobutylene) side chains. It was shown by small angle neutron scattering in toluene at 11 g/L that U2PIB2 selfassembled into small objects exhibiting a weight average aggregation number of 8.5.…”

Can the Structures of Semicrystalline Polymers be Controlled Using Interfacial Crystallographic Interactions?

“…Dynamic Monte Carlo simulations indicate that, at high temperatures, thin polymer films on a slippery surface grow dominantly in edge‐on lamellar crystals, while flat‐on lamellar crystals are mainly observed on a sticky substrate 45. Reiter and Hu et al46–52 have performed experimental investigations on thin and ultrathin film crystallization of polymers. Abundant experimental results indicate that thin polymer films of tens to hundreds of nanometers crystallized at relatively lower supercoolings are in favor of a specific orientation, namely typical thin lamellar crystals with the molecular chains normal to the substrate (i.e., the lamellae lie “flat‐on” against the substrate 53–69.…”